The treatments for adolescent long closed mouth acne include general treatment, medication, and physical therapy. 1. General treatment: keep the affected area clean, don’t use irritating toiletries or cosmetics, don’t excessively squeeze the acne area with your hands, and avoid eating oily, high-sugar foods and dairy products. 2. Medication: Adapalene gel can be applied to help dissolve and discharge acne, and when combined with infection, mupirocin ointment can be used externally for treatment, and in severe cases, oral medication, such as doxycycline and minocycline, should be used. 3. Physical therapy: For closed mouth acne, physical therapy can also be carried out, such as red and blue light therapy, photodynamic therapy, chemical exfoliation therapy and so on. During the treatment period, you should follow the doctor’s instructions, safe and reasonable application of topical as well as oral medications, do not use drugs indiscriminately.