Acne scars develop because of the severity of skin inflammation. This can be traced to genetic predisposition or unusual healing of acne blemishes. The genes determine how much damage acne causes to the skin, how well the skin heals, and how much collagen is produced. Significant acne scars may also develop or worsen by picking and popping pimples. The risk of permanent acne scarring can be because of untreated inflammatory acne that occurs deep in the skin. Acne scars can be worse if the acne is squeezed, picked, or popped. They can even become severe if people smoke tobacco. Cigarette smoking impairs the natural healing of the skin.