Depressed scar

Depressed scar sit below the surface of the skin and have a sunken or pitted appearance. Acne is common cause of the pitting scar.

Treatment
#Ice pick scar - TCA peeling (CROSS technique)
#Rolling scar - Laser resurfacing by Erbium laser or fractional laser
      References Methods for the Improvement of Acne Scars Used in Dermatology and Cosmetology: A Review 35628870 
      NIH
      Acne vulgaris is a chronic skin disease that, depending on its course, is characterized by the occurrence of various skin eruptions such as open and closed comedones, pustules, papules, and cysts. Incorrectly selected treatment or the presence of severe acne vulgaris can lead to the formation of atrophic scars. In this review, we summarize current knowledge on acne scars and methods for their improvement. There are three types of atrophic scars: icepick, rolling, and boxcar. They are of different depths and widths and have different cross-sections. Scars can combine to form clusters. If acne scars are located on the face, they can reduce the patient's quality of life, leading to isolation and depression. There are multiple effective modalities to treat acne scars. Ablative lasers, radiofrequency, micro-needling, and pilings with trichloroacetic acid have very good treatment results.
       A systematic review and meta-analysis on the effects of the ultra-pulse CO2 fractional laser in the treatment of depressed acne scars 35249351
      This study examined 6 papers about how well the ultra-pulse CO2 fractional laser treats depressed acne scars. The results showed that this laser treatment was more effective compared to other methods, leading to better outcomes in terms of improvement rates and how smooth patients' skin felt.