As its name suggests, cystic acne is a severe form of acne that results in large, pus-filled cysts forming underneath the skin’s surface, which usually makes them much more painful than normal bumps and, depending on the severity, can cause scarring, according to Dr. Emma Weiss, a board-certified dermatologist and assistant professor of dermatology at the University of Colorado, Anschutz Medical Campus. Though this type of acne can be hard to treat, it’s not impossible, and the dermatologists we spoke to recommend treating cystic acne as soon as possible to avoid permanent scarring.