Serious acne, also known as severe acne or cystic acne, is characterized by deep, painful cysts, nodules, and inflammation. It can be larger, more inflamed, and can lead to scarring if not treated properly. Serious acne often covers larger areas of the face, back, or chest and does not respond well to over-the-counter treatments. It is essential to consult a dermatologist for proper diagnosis and treatment if you suspect you have serious acne.