When you have a blister next to your mouth, the first thing to check is whether it is herpes, which usually comes in clusters and can be painful and itchy. If it is herpes, note that it is caused by the herpes simplex virus, and antiviral treatment should be administered. Commonly used drugs include acyclovir, vaxilovir, and you can use ribavirin, which is a virazole, a broad-spectrum antiviral drug that is more effective. In addition, topical antiviral medications, such as acyclovir ointment, or compounded boric acid solution can be used for disinfection and sterilization. If the blisters next to the mouth are caused by long-term lip biting, this is not herpes, but a submucosal mucous gland cyst, which usually requires surgical removal to resolve, and is prone to recurrence, it is recommended to correct the bad habits of lip biting and lip licking.