When untreated acne penetrates deeply into the skin, it can damage the underlying skin and the tissue. As acne is treated or when it clears, the body tries to repair the damage left behind.
During this healing process, the fibroblasts in the dermis (second layer of skin) produce a substance called collagen.
Collagen acts as the framework, providing support to the epidermis (top layer of skin).
The incorrect amount of collagen in the wrong area will potentially create a scar and unevenness to the skin.
There are two main types of scars, each depends on how much collagen your body makes: