Severe acne is more than just an inconvenience — it is stubborn, , and can be extremely painful, leaving emotional and in its wake. Those who experience more extreme (from cystic acne to more serious immune responses) understand just how harrowing the process of identifying and treating these skin conditions can be. It's more complicated than popping on a hydrocolloid patch and changing your pillowcase.

To get a better understanding of the different types out there, as well as severe acne treatment options, we tapped board-certified dermatologist , MD — a leading expert on sensitive skin at Memorial Sloan Kettering Cancer Center — to give us a rundown on the main forms, what causes them, and the most effective ways to treat them. But first, what is considered severe acne? "Severe types have larger, inflamed cystic nodules that can be painful and result in pitted severe acne scars, as well as hyperpigmentation and dermal skin atrophy," Dr. Rossi tells PS.

Acne is extremely common — in fact, it's the most common skin condition among teens, with up to experiencing moderate to severe forms of acne. While there are varying types of severe acne and many ways to treat them (more on that below), there are two main commandments, according to Dr. Rossi: "Do see a board-certified dermatologist, and don't pick, pop, or squeeze.

" "This is part of a group of skin disorders called the follicular occlusion tetrad," Dr. Rossi says, meaning acne conglobata has friends in low places —.