Acne scars are caused by the body's response or a better word to use should be over response to injury caused by inflammatory acne lesions.
Scarring often results from severe nodular acne that occurs deep in the skin.
Scarring actually refers to a process in which new collagen is laid down to heal an injury.
Collagen is important to the skin because it is a protein that gives the skin its rigidity and strength.
Collagen is produced by fibroblasts found in the dermis.
Fibroblasts are responsible for the repairing of any injury that takes place.
Collagen in the dermis is required to patch up any damage in the skin.
When there is any overproduction of collagen, the excess collagen becomes piled up in the fibrous masses producing a firm scar.
Propionibacterium acnes bacterium can add to the damage when it releases tissue-destroying chemicals that results in the damage of normal collagen and hence scarring.
Acne scars are the visible reminders of where the body's inflammatory battle against an acne lesion took place.
The deeper an acne lesion is lodged in the skin, the greater the chance of scarring.
    Acne scars can take on a number of different appearances: they may be flat, bulging out or indented.
These acne scars may also come in different colors.
They could be skin color, whitish, purple, red, or even darker than the normal skin color.
Some people endure their acne scars all their lives with little change in them.
For others, their skin condition might improve and the scars undergo some degree of improvement over time and these scars sometimes remodel and decrease in size.