Acne Scar Treatment: How a Dermatologist Picks the Tool

This is an English adaptation of a clinical article Dr. SangYoul Yun — board-certified dermatologist and Medical Director of Delight Dermatology in Gangnam, Seoul — originally published in Korean. Read the Korean original on Naver. It has been restructured and translated for international readers; all references are the author's own.

"Will one laser get rid of my scars?" It is the question I hear most — and one of the most disappointing misconceptions. Many people think of scar treatment like choosing a cosmetic: find the "single best procedure." But scars form by different mechanisms depending on type, so the tool has to differ too. You can't loosen a screw with a hammer. Here I'll be honest about the tools we actually use, and how I choose which one for which scar.

(If you first want to understand the scar types themselves — icepick, boxcar, rolling, keloid — see the companion piece on the four acne scar types. This article is about matching tools to those types.)

Scars fall into two big groups

To understand the treatment direction, start with this split.

• Depressed (atrophic) scars → icepick · boxcar · rolling → skin is "sunken" → treat by filling / raising collagen back up.
• Raised (hypertrophic · keloid) scars → skin "protrudes" → treat by flattening the excess tissue back down.

The crucial point is that the treatment directions are opposite. Using a "filling" procedure on a raised scar can actually make it worse. So scar treatment begins not with "what procedure will I get," but with accurately diagnosing which side my scar is on.

1. Tools for filling depressed (atrophic) scars

The most common — and most demanding — area. We choose from four tools to match the scar shape, and usually combine two or three.

① Subcision — the key for rolling scars

Wide, gently undulating rolling scars are a problem of the underside, not the surface: fibrous tissue beneath the scar tethers the skin inward and holds it down. That is why surface-only lasers have limits. Subcision inserts a fine needle or blunt cannula beneath the scar to cut the tethering fibrous bands. As the adhesion releases, the sunken area lifts and new collagen fills in. The evidence is solid: in a cannula-subcision study, about 83% of patients showed "good to very good" improvement.¹ Deep scars do tend to recur, so we usually combine it with other procedures.

② Microneedle RF — remodelling the whole dermis

Fine needles are inserted into the skin and deliver radiofrequency (RF) heat precisely to the deep dermis. The key is that it barely touches the surface (epidermis) while stimulating deep collagen regeneration. Its biggest advantages are short downtime and safety for Korean/Asian skin. Lasers can stimulate melanin and carry a pigmentation risk; microneedle RF uses electrical rather than light energy, so the risk of pigment side effects is lower. Studies comparing it with lasers consistently conclude that "the laser gives slightly more scar improvement, but microneedle RF has shorter downtime and less pigment risk."² That is exactly why busy working patients favour it. In clinic we deliver this through Potenza microneedle RF.

③ Pico fractional — resurfacing that also clears pigment

A fractional pico laser fires energy in picosecond (one-trillionth of a second) pulses. Because the energy enters in such a brief instant, surrounding heat damage is small, and it can refine the scar's surface texture while also improving pigmentation (red and brown marks) at the same time. With acne scars, the leftover pigment marks often bother patients more than the scar itself — pico fractional suits those cases well. In Asian-skin studies it showed improvement comparable to conventional fractional laser, with shorter downtime.³

④ Genesis — finishing texture and redness

A low-irritation laser that gently heats the dermis to tidy skin texture and fine redness. Rather than a procedure that dramatically flattens scars on its own, we use it as a finishing step to smooth overall tone and texture after the procedures above. It is gentle enough to return to daily life immediately.

The key — for depressed scars, "combination" is the answer. In studies, the group that had subcision plus microneedling improved more than either alone (combination 100% vs. monotherapy 77%).⁴ That is why we don't recommend a single procedure.

2. The tool that "prevents" new scars — acne peels

The most important thing in scar treatment is actually not creating new scars. If you treat scars while active acne keeps erupting, a new scar forms on one side while you fill the other. An acne peel (chemical peel) clears keratin and sebum from the pores, calms inflammatory acne, and gently improves shallow scars and pigment marks. It is the "groundwork" stage of scar treatment. For anyone with active acne, this is usually where we start.

3. The tool for calming raised (keloid) scars — intralesional injection

Hypertrophic scars and keloids are firm, raised, sometimes itchy or stinging — and need the opposite approach from Part 1. Not filling, but pressing the overgrown tissue back down. The core here is intralesional injection: typically a steroid (triamcinolone) injected directly into the scar to suppress excess tissue growth. Keloids, though, are demanding — about half of keloids do not respond well to steroid alone or recur.⁵ For these, steroid combined with 5-fluorouracil (5-FU) is a recognised option.⁶

A warning: keloids are dangerous to self-diagnose. Grinding a raised scar with a laser as if it were a depressed scar can irritate it and make it grow larger. The direction must be decided after diagnosis.

The three principles of scar treatment

• Diagnosis first. Before "which procedure," the question is "is my scar the depressed or raised kind, and which type?"
• One tool is not enough. Scars usually have mixed causes, so results are best when tools are combined.
• Realistic expectations. Scar treatment "makes scars less noticeable," it doesn't "erase" them. Improvement is usually gradual, over several sessions.

Scars are often carried for a long time and can weigh on the mind. But with accurate diagnosis and the right combination of tools, they genuinely improve. Don't rush — start by building a plan that fits your skin. Where scars are extensive or long-standing, we plan a staged course through our acne scar treatment and advanced scar treatment, matching the tools above to your skin one-to-one.

References

1. Ahramiyanpour N, et al. Subcision in acne scarring: A review of clinical trials. J Cosmet Dermatol. 2023;22:744–751.
2. Comparative study on 1550nm Er:Glass fractional laser vs fractional radiofrequency microneedle for facial atrophic acne scar. PubMed 25810322.
3. 1064-nm Picosecond Laser vs Fractional Laser for Atrophic Acne Scars in Asian Patients (Randomized Split-Face Study).
4. Ahramiyanpour N, et al. 2023 (review above, ref 1) — microneedling + subcision combination 100% vs monotherapy 77.1% improvement.
5. Acharya R, et al. Intralesional triamcinolone alone vs combination with 5-FU in keloids and hypertrophic scars. Skin Health Dis. 2024.
6. Efficacy and Safety of Intralesional Triamcinolone vs Triamcinolone + 5-Fluorouracil: Systematic Review and Meta-analysis. PubMed 32342167.

Medical disclaimer. This article is general information and does not replace individual consultation. Treatment methods and results vary with each person's skin condition; the accurate diagnosis and treatment plan must be decided through a specialist consultation. In particular, raised scars and keloids require diagnosis before any laser or injection, and intralesional medicines (steroid, 5-FU) require a doctor's care.