A mouth cyst is a thin, fluid-filled sac on the inside of your mouth. Also called a mucous cyst or mucocele, the sac is harmless and painless. These cysts commonly occur on the inside of the lips but can also form on your tongue, palate, inside of the cheeks, floor of the mouth or around piercings on the tongue or lips. A cyst on the floor of your mouth is called a ranula, and a cyst on the gum is called an epulis. The mucocele sac is bluish and clear and contains clear fluid. Your dentist can usually diagnose a mucous cyst just by looking at it.
The cause of these fluid sacs on the lips, gums or inside of the cheeks is believed to be sucking the tissue between your teeth. Not intentionally sucking your cheeks or lips may prevent some cysts from forming, but some cysts can appear at random. Sometimes, your dentist or an oral surgeon will choose to surgically remove the cyst, especially if it returns after being opened. Complications of surgery are very rare, involving the standard risks of surgery such as infection or an adverse reaction to the local anesthesia. Always talk to your dentist or dental specialist and make sure you understand the risks. If the cyst does not open on its own and you do not receive treatment, a permanent bump may form. These bumps are harmless, but see your dentist if something new forms in your mouth and you have concerns. It is important to make sure that the dentist evaluates this area by examination and an x-ray, if needed. Your oral health is a part of your total health.