Analysis of your situation may be that you are keloid and have scar growth. Keloid is the overgrowth of dense fibrous tissue, which usually occurs after skin injury. This kind of tissue hyperplasia is beyond the scope of the original injury and cannot be resolved by itself.

Suggestion:

From the beauty point of view, I suggest that you treat that acne by surgery, laser, radiation, pressure, silica gel membrane, freezing and other methods.