Boxcar scars have sharp walls and a flat floor. Medical Director Dr Sin Yong matches resurfacing, release and support to their depth at IN Eternity Clinic on Orchard Road.
WhatsApp to Enquire →Key facts ↓Boxcar scars are round or oval acne scars with steep walls and a flat floor, usually 1.5 to 4 mm across. Shallow ones respond to fractional CO2 or RF microneedling, which soften the edge. Deep ones need more: subcision if the floor is tethered, focal treatment of the walls and sometimes filler support. Most people need three to six sessions; scars soften, they are not erased.
Boxcar scars are round or oval depressions with steep, almost vertical walls and a broad, fairly flat floor, a little like the outline of a railway boxcar seen from the side. They are usually 1.5 to 4 mm across, wider than ice pick scars, and they are most common on the cheeks and temples. In side light the sharp edge throws a crisp shadow, which is what makes them visible; in flat light they can almost disappear.
Doctors divide them by depth because depth changes the plan. Shallow boxcar scars (roughly 0.1 to 0.5 mm deep) sit within reach of resurfacing. Deep boxcar scars (deeper than about 0.5 mm) usually need more than one step, because the floor lies below what a resurfacing pass can remodel and is sometimes tethered by fibrous strands.
Most people with boxcar scars also have rolling or ice pick scars nearby. How the types differ is set out in types of acne scars.
A boxcar scar starts as an inflamed spot that sits deep enough, and lasts long enough, to break down collagen across a wider area than an ice pick scar. As the spot heals, the lost collagen is not fully replaced and the floor settles lower than the skin around it, leaving a sharp-edged step.
The single most useful prevention is early, effective acne treatment, because each deep spot that is controlled is a scar that does not form.
| Boxcar | Rolling | Ice pick | |
|---|---|---|---|
| Shape | Steep walls, flat floor | Soft, sloping edges; wave-like | Narrow V-shaped shaft |
| Width | About 1.5–4 mm | Often 4–5 mm or wider | Under about 2 mm |
| Stretch test | Stays visible | Softens or flattens | Stays visible |
| What holds it down | Lost collagen; sometimes tethering at the floor | Fibrous bands tethering the skin | A deep narrow tract |
| Usual first tool | Fractional CO2 or RF microneedling; subcision if tethered | Subcision | TCA CROSS or CO2 point shots |
Rolling scars are covered on rolling acne scars and subcision, and ice pick scars on ice pick scar treatment.
| Scar | Usually first | Often added | Typical sessions |
|---|---|---|---|
| Shallow boxcar | Fractional CO2 (S3 protocol) or RF microneedling to soften the edge | Pico laser for texture; skin boosters for skin quality | About 3–4, four to eight weeks apart |
| Deep boxcar, not tethered | CO2 point shots or TCA CROSS to the walls, then a fractional pass | A filler or collagen stimulator under the floor | About 4–6 |
| Deep boxcar, tethered floor | Subcision to free the floor | Resurfacing four to six weeks later; support where volume is lost | About 4–6 across the steps |
“A boxcar scar has an edge and a floor. Soften the edge and the shadow fades; if the floor is tied down, the laser alone will not lift it.”
Boxcar scars respond to heat-based resurfacing, and heat is what raises the risk of post-inflammatory darkening in skin types III to V. The balance is struck with settings and sequence rather than by avoiding treatment. Density is kept moderate, sessions are spaced six to eight weeks apart, heavy steps are not stacked, and RF microneedling is often used where the skin darkens easily. Sun protection that also covers visible light continues every day of the course.
Fractional CO2 has been studied in Asian patients with atrophic acne scars, with improvement over several sessions and darkening as the main side effect, usually temporary. Your own pigment history, how your skin darkened after spots or sun, is the most useful guide to how conservative the plan should be.
Collagen remodels for months after each session, so boxcar scars are treated as a course and judged on photographs taken in the same light. Shallow scars often need three or four sessions; deep or tethered scars more, across several methods. The realistic aim is a softer edge, a shallower floor and less shadow in side light, not skin that was never scarred.
| Step | Visible recovery | Spacing |
|---|---|---|
| Fractional CO2 | About 5–7 days of redness and crusting | 6–8 weeks |
| RF microneedling | About 2–4 days of redness | 4–6 weeks |
| TCA or CO2 to the walls | Small crusts for about a week | 4–6 weeks |
| Subcision | Bruising and swelling for 1–2 weeks | Then 4–6 weeks before resurfacing |
| Filler or collagen stimulator | Small bumps or bruising for a few days | Product-dependent |
Only a little, and mostly around the scars rather than in them. A retinoid used at night and regular superficial peels can make the skin surface finer and more even, which slightly softens how the edges catch the light. They do not rebuild the lost collagen under a boxcar floor, so the step remains. Facials and skin boosters improve hydration and skin quality and can make shallow scarring look less obvious, but they do not lift a scar; see what an acne scar facial can do and skin boosters for acne scars.
Two habits matter more than any product. Daily sunscreen keeps the skin around the scars from darkening, which makes the shadows look deeper. And not picking new spots is the most effective way to stop new boxcar scars forming while the old ones are treated.
General clinical observations used at consultation; they describe what is checked, not any individual result.
Cost depends on how many scars and areas are treated, whether they are shallow or deep, which methods are combined and how many sessions are needed. Other Singapore clinics publish fractional CO2 at S$380 to S$600 per session and RF microneedling at S$600 to S$1,500 per session (read 20 October 2026; sources in acne scar removal cost in Singapore). At IN Eternity Clinic the plan is quoted after assessment; the consultation fee is S$120, waived with any medical treatment. Every option is set out on acne scar treatment in Singapore.
Boxcar scars are round or oval acne scars with steep, almost vertical walls and a flat floor, usually 1.5 to 4 mm across. They form when deep inflammation destroys collagen across a wider area and the floor heals lower than the skin around it.
They can usually be made shallower and softer-edged so they throw less shadow, but complete removal is not a realistic promise. Shallow boxcar scars tend to respond more than deep ones.
Fractional CO2 is commonly used to soften the edge and remodel collagen, with about a week of recovery. RF microneedling, which is not a laser, is often chosen for skin that darkens easily. Many plans use both.
Only if the floor is tethered. If a deep boxcar scar softens when the skin is stretched, its floor may be tied down, and subcision to free it usually comes before resurfacing.
A filler or collagen stimulator can lift a broad floor that stays low, usually after release and alongside resurfacing. It does not soften a sharp edge on its own.
Shallow boxcar scars often need three or four sessions; deep or tethered scars need more, across several methods. Sessions are usually four to eight weeks apart.
Other Singapore clinics publish fractional CO2 at S$380 to S$600 per session and RF microneedling at S$600 to S$1,500 (read 20 October 2026). The total depends on the scars, methods and sessions. At IN Eternity Clinic the consultation fee is S$120, waived with any medical treatment.
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. The consultation fee is waived with any medical treatment.
These sources describe mechanisms and general evidence. They are not a promise of any individual result; suitability is decided at an in-person assessment.