Blisters on fire at the corners of the mouth may be herpes labialis, xerostomia, etc. The corresponding treatments are antiviral treatment, anti-bacterial and fungal treatment, etc. 1. Herpes labialis: it usually heals spontaneously in about a week. Be careful not to scratch, try to break it or overstimulate it. Topical antiviral agents, such as 5% acyclovir ointment, can be used if necessary. 2. Keratitis: For bacterial infection, give antibiotic ointment such as erythromycin. For fungal infections caused by keratitis need to give clotrimazole cream and other antifungal drugs to rub. The medication needs to be used under the guidance of a doctor. The corners of the mouth on fire blisters may also have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.