Blisters on the inside of the lower lip may be caused by bad habits of lip biting or lip licking, resulting in mucous gland cysts on the lower lip. Usually, there are small mucous gland glands on the lower lip, which tend to block the ducts of the glands when lip-biting is not done carefully, and small transparent blisters, possibly light blue in color, will appear, and this condition usually requires surgical excision for treatment. You can go to the stomatology department for local anesthesia, and then outpatient surgical excision, excision needs to be sutured, usually about a week to remove the stitches, it is recommended to maintain good oral hygiene, to correct the bad habits of biting or licking the lips, in order to avoid the recurrence of the phenomenon. It is recommended to maintain good oral hygiene, in order to ensure that to avoid the phenomenon of bacterial infection, if there are symptoms of infection, should be timely oral antibiotics to prevent infection, such as amoxicillin or erythromycin.