A small blister under the tongue may be a cyst of the sublingual gland, which can be treated with injections of anhydrous ethanol, laser, or by taking a surgical procedure to remove it.
Sublingual gland cysts are usually located in the base of the mouth under the tongue, which can be translucent and light purple-blue in color, with soft texture and fluctuating sensation. When the cyst ruptures, there can be yellowish, egg-white-like mucus flowing out, which can be treated by local injection of anhydrous ethanol, etc. However, the radical treatment is sublingual gland excision, and it can be treated by laser, microwave thermo-coagulation and freezing methods.
Therefore, it is recommended to go to the regular hospital in time, to clarify whether it is caused by the above causes, to avoid blind disposal, so as not to cause aggravation of the condition and adverse consequences.