Acne, also known as pimples, is categorized as papular acne, pustular acne, cystic acne, and nodular acne, depending on the clinical presentation. 1. Papular acne is mainly characterized by raised pimples and localized redness. 2. Pustular acne is an exacerbation of papular acne, which is characterized by a suppurative infection, accompanied by significant redness, swelling, and hot pain. 3. Cystic acne is characterized by subcutaneous cystic masses that are painful to touch and soft. 4. Nodular acne is characterized by painful, hard lumps on the facial skin. The treatment of different types of acne can vary, so it is important to consult a doctor for specific types.