Blisters on the outside of the mouth may be caused by physiological factors such as lack of sleep, improper diet, etc. and do not require special treatment. It may also be caused by herpes orofacialis, oral herpes simplex and other conditions, the patient needs to follow the medical advice for drug treatment, general measures and so on. 1. Physiological factors: usually for poor living habits, often stay up late, sleep deprivation, or often eat spicy and stimulating food patients, may appear outside the mouth blistering phenomenon. Most patients can recover on their own after improving their living habits and standardizing their diet, without special treatment. 2. Oral and lip herpes: Usually patients can follow the doctor’s instructions to use 3% acyclovir ointment, 1% penciclovir cream and other medications, if secondary infection occurs, but also with the use of 0.05% ~ 0.1% chlorhexidine liquid, mupirocin ointment. Some patients also need oral or intramuscular acyclovir, vasiclovir and other antiviral drugs to shorten the course of the disease and reduce recurrence. 3. Oral herpes simplex: patients can follow the doctor’s instructions for local use of 3% acyclovir ointment, 1% penciclovir cream, etc., with anti-inflammatory and analgesic effect, can promote healing. The disease is self-limiting, patients usually need to pay more attention to rest, if there is difficulty in eating, but also need to pay attention to supplemental vitamins and protein. It is recommended that patients with blisters on the outside of their mouths should first exclude physiological factors, and then identify the cause of the disease and treat it reasonably. All of the above drugs should be used in accordance with medical advice.