Acne can be caused by acne and folliculitis. Acne can be treated by applying creams such as retinoic acid cream as prescribed by the doctor; folliculitis can be treated with different creams depending on the pathogen of the infection. 1. Acne: Acne patients can apply medications such as retinoic acid cream and benzoyl peroxide gel for treatment, which can dissolve microcomedones, reduce inflammation and improve acne symptoms. 2. Folliculitis: If the folliculitis is caused by Malassezia infection, patients can apply ketoconazole cream, miconazole cream and other antifungal cream for treatment to inhibit the reproduction of Malassezia and improve the symptoms of acne. If the folliculitis is caused by bacterial infection, patients can apply mupirocin ointment, fusidic acid cream and other drugs to treat it. It is recommended that patients with acne on their backs go to the hospital for examination, make a clear diagnosis and then carry out standardized treatment under the guidance of doctors.