Canker sores on the buttocks are most often the result of folliculitis and boils that are not well controlled, and a more serious bacterial infection occurs, which can appear as a well-defined lump on the buttocks. In clinical treatment, sodium penicillin injection or cefothiamidine injection can be ordered quietly, and if the above drugs are allergic, clindamycin phosphate injection or levofloxacin hydrochloride injection can be chosen. Topical medications can be applied with local wet compresses or rinses of ezacrine lactate, or 1:5000 potassium permanganate solution can be selected for local rinses to achieve anti-inflammatory and antiseptic effects, and compound polymyxin B ointment or mupirocin ointment can be selected for application after external washing to strengthen anti-inflammatory treatment.