Acne scars are broadly classified into atrophic scars, which are sunken, and hypertrophic and keloid scars, which are raised. Atrophic scars are further classified into narrow and deep “ice-pick” scars, wide “boxcar” scars with distinct borders, and “rolling” scars that are widely indented with gentle borders. Treatment approaches vary depending on the scar type and may include chemical peels (including TCA CROSS), lasers, fractional lasers, microneedling (collagen induction), and dermabrasion to smooth the surface, fillers to fill in depressed areas, subcision to sever fibrous bands beneath the scar, and punch excision to remove raised scars. For hypertrophic and keloid scars, treatments such as intralesional steroid injections, silicone dressings, pigment lasers, and cryotherapy are used. A combination of multiple methods is often recommended rather than relying on a single approach. Since the method and recovery process vary depending on the type, depth, and skin type of the scar—and multiple sessions may be required—it is important to discuss this during a consultation. This information is for educational purposes only and does not constitute a diagnosis. Please consult a specialist regarding actual procedures.
[Source] https://dermnetnz.org/topics/acne-scarring