What a Rejuran injection session leaves behind, and how to care for your skin afterwards. Dr Sin Yong at IN Eternity Clinic on Orchard Road walks through the first two weeks.
WhatsApp to Enquire →Key facts ↓Rejuran downtime is usually short. Small raised bumps at each injection point are expected and mostly settle within several hours to a day or two; redness fades over a similar time, and pinpoint bruises can take up to a week. Most return to work the next day. Aftercare means gentle skincare, sun protection and briefly avoiding heat and exercise.
Rejuran is a polynucleotide gel made from purified salmon DNA. Unlike a filler, it is not placed deep to change shape. It is placed shallowly, in the upper dermis, as many small deposits across the treated area, usually after numbing cream. Each deposit is a tiny volume of gel sitting under thin skin, so it raises a small bump, similar to the bleb you see when a vaccine is given just under the skin.
Those bumps are part of correct placement, not a reaction. Over the following hours the gel spreads into the surrounding tissue and draws in water, and the surface flattens. Rejuran S, the thicker gel used for scars, can leave firmer bumps for a little longer. Rejuran i, the thinner under-eye formulation, tends to leave smaller ones. Formulations are compared in Rejuran Healer vs HB vs S vs Eye.
Before injecting, the skin is cleansed thoroughly, make-up is removed and a numbing cream is applied for around 30 to 45 minutes. Dr Sin Yong then maps the areas to be treated and places the product row by row at a consistent shallow depth. The visit takes about an hour in total, most of which is numbing time. A calming, fragrance-free moisturiser is applied at the end, and the aftercare below is explained before you leave.
Day 0. Rows of small bumps, pinkness and mild tenderness across the treated area. Some people see tiny blood spots at the entry points. The skin can feel warm and tight for a few hours. Most bumps are noticeably smaller by bedtime.
Days 1–3. Most bumps have flattened by the next morning; a few, especially on thinner skin or where Rejuran S was used, may still be felt for one or two days. Any remaining redness is usually light enough for make-up once the skin has closed. Pinpoint bruises may become more visible on the second day before they begin to fade.
Week 1. Bruises fade through yellow to normal over about five to seven days. The skin may look slightly more hydrated, but this early change is mainly water and settling, not the result.
Weeks 2–4. Any change in texture, fine lines and resilience develops gradually as the skin responds. The next session in a course is usually booked three to four weeks after the last.
Review. The effect is judged after the course, against photographs taken at the first visit, rather than after a single session.
“The bumps tell me the product is sitting where it should. At review I want to know how your skin behaves three weeks later, not that evening.”
For the first day, keep the skin clean and leave it alone. Wash gently with lukewarm water and a mild cleanser in the evening, pat dry and apply a plain moisturiser. Avoid make-up for the period advised at your visit so that the entry points can close. A cool pack wrapped in a clean cloth can ease warmth and swelling for short periods.
For the first 24 to 48 hours avoid saunas, steam rooms, hot yoga, strenuous exercise and alcohol, which all increase blood flow and can make swelling and bruising worse. Avoid pressing or rubbing the bumps; unlike some collagen stimulators, polynucleotide does not need massage, and pressing on the skin only irritates it. For the first few days pause retinoids, exfoliating acids, scrubs and devices such as cleansing brushes, then reintroduce them gradually.
Sun protection matters every day in Singapore, and more so while the skin is pink. Use a broad-spectrum sunscreen once the entry points have closed and a hat outdoors. Skip swimming pools for a day or two. General guidance on caring for treated skin is on the aftercare page.
When you restart your usual routine, bring products back one at a time over a few days: a gentle cleanser and moisturiser first, then vitamin C or niacinamide if you use them, then retinoids and exfoliating acids last. If anything stings, stop it for another day or two. Skin that was sensitised before treatment benefits from a simpler routine for the whole course, and Dr Sin Yong may suggest specific barrier-repair products to use between sessions.
Downtime varies with skin and with technique. Thin, fair skin shows bumps and pinkness more clearly; skin that bruises easily will bruise more. Aspirin, other blood thinners, fish oil, vitamin E, ginkgo and alcohol before treatment all increase the chance of bruising. Never stop a prescribed medicine on your own; tell the doctor what you take so the plan can account for it.
Technique matters too. Manual injection with a fine needle gives control over depth and amount at each point. Injector systems and needle-free jet delivery spread product differently; a small comparison study of needle injection and a needle-free jet injector for polynucleotide reported that both improved skin measures, with differences in comfort and visible marks. How many areas are treated in one visit, and whether the thicker S formulation is used, also changes how much you see afterwards. If downtime matters to you, say so at consultation and the plan can be adjusted, for example by treating fewer areas per session.
Most people return to office work the next day, and many the same afternoon if they are comfortable with visible bumps. If you have a wedding, a photo shoot or an important presentation, book at least a week ahead so that any bruise has time to fade; two weeks gives more margin. The downtime planner sets out typical recovery windows across treatments if you are combining Rejuran with other work.
If Rejuran is part of a wider plan, energy-based treatments and resurfacing are usually spaced from the injection session so that swelling from one does not mask or aggravate the other. Dr Sin Yong will set out the order and spacing for your course.
Across a course of three sessions, downtime is usually similar each time, though some people notice that bumps settle a little faster at later visits once they know what to expect and follow the aftercare closely. If one session left more bruising than you were comfortable with, mention it at the next visit: the number of areas, the formulation or the technique can be adjusted, and supplements that increase bruising can be reviewed in advance.
Contact the clinic promptly if pain increases after the first day instead of easing, if an area becomes hot, swollen or increasingly red, if small pus spots appear, or if you develop a fever. These can be signs of infection, which is uncommon but needs early treatment. Hives, widespread itching, swelling of the lips or eyelids, or difficulty breathing need urgent medical attention, as they can be signs of an allergic reaction.
Lumps that are still present after about two weeks are reviewed in person. Most are small collections of gel that soften with time; occasionally a firmer nodule needs assessment. A published series on long-chain polynucleotide reported mostly mild, temporary reactions, alongside occasional lumps, which is why follow-up is part of the plan. WhatsApp the clinic on +65 8815 3008 with a clear photograph if you are unsure.
Most Rejuran bumps flatten within several hours to a day as the gel spreads into the surrounding skin. A few may still be felt for one or two days, particularly on thin skin or where the thicker Rejuran S was placed into scars. Bumps that are still present after about two weeks should be reviewed at the clinic.
Most people go back to work the next day, and some return the same afternoon if they do not mind visible bumps. Pinpoint bruises are possible and can usually be covered with make-up once the entry points have closed. If you have an important event, book at least a week ahead to allow any bruise to fade.
Make-up is usually avoided for the period advised at your visit, often until the next morning, so the tiny entry points can close and bacteria are not pushed into them. Use clean brushes or sponges when you restart, and choose a gentle product for the first few days.
Light walking is fine. Avoid strenuous exercise, hot yoga, saunas and steam rooms for 24 to 48 hours, because heat and raised blood flow can increase swelling and bruising. Skip swimming pools for a day or two while the entry points heal.
Numbing cream is applied for around 30 to 45 minutes before treatment, and most people feel a series of quick pricks and a mild sting as the gel goes in. Thinner areas and around the nose and mouth feel more. Rejuran HB contains lidocaine for added comfort. You can ask for a pause at any time.
Contact the clinic if pain increases after the first day, the area becomes hot, swollen or increasingly red, pus spots appear or you feel feverish, as these can suggest infection. Hives, lip or eyelid swelling or breathing difficulty need urgent medical attention. A lump still present after two weeks should be reviewed in person.
Cost depends on the formulation, the number of syringes, the areas treated and how many sessions the course needs. Downtime does not change the price, but if you need minimal visible marks the plan may be spread over more, smaller sessions. Dr Sin Yong gives a written, itemised quote after assessment.
IN Eternity Clinic, 9 Scotts Road, #12-01 Pacific Plaza, Singapore 228210. By appointment with Medical Director Dr Sin Yong. Monday to Saturday, 11am to 8pm. WhatsApp or call +65 8815 3008.
These sources describe mechanisms and general evidence. They are not a promise of any individual result; suitability is decided at an in-person assessment.