Acne develops when pores become blocked with dead skin cells and oil. They usually disappear over time but sometimes they leave a scar. When those blemishes form white blood cells rush to the surface to help heal the area. But occasionally a scar forms. Popping and picking can send bacteria further into the skin and increase the blemish and it greatly increases the likelihood that a scar will appear. Nodules and cysts are more severe blemishes and have an increased likelihood of leaving scars. Scars are caused by loss of skin or excess collagen. One treatment involves having collagen injected into the scar area. Fat from another area of the body can also be injected to help with the scarring. In both of these cases the effects of the injections are temporary lasting roughly six months. A dermatologist can also inject corticosteroids into the area. Another treatment involves the use of lasers. The results are hard to achieve, expensive, and may take multiple treatments to achieve the desired result. Another treatment is called dermabrasion. It involves using high-speed brushes to remove excess skin. If the scars are too severe they may require skin surgery. Prevention is better than trying to treat the scars.