The dark brown acne marks are pigmentation after the inflammatory reaction of acne. After mild acne heals, the pigmentation will slowly fade in 3-6 months and fade on its own. Patients with dark skin acne are more likely to have acne marks than those with white skin, and the acne marks last longer.
If the fading of pigmentation is not satisfactory, it is recommended to go to the dermatology department of a regular hospital for treatment in a timely manner.