A white bump or cyst on the inside of the lip is a mucus cyst, also called a mucocoele, according to Skinsight. It can form anywhere but is usually found on the lower lip.
A white bump or mucous cyst forms on the lip when the salivary glands get blocked. This is caused by any trauma to the oral cavity due to cheek or lip biting, poor dental habits, or piercings, states Healthline. The symptoms associated with these cysts depend on how frequently they form and how deep the cyst has gone into the skin. Mucus cysts that are superficial or close to the surface of the skin appear as a raised swelling that has a bluish tinge and is soft to the touch. Deeper cysts are white, feel like a nodule or bump and are tender to the touch.
Cysts are usually painless and temporary, but recurring cysts can become permanent if left untreated, according to Healthline. If there is no history of trauma and a cyst doesn't heal for more than two months or is larger than 2 centimeters, a biopsy is needed to rule out lipoma or cancer. Small cysts don't require treatment and usually disappear on their own. Frequently recurring cysts can be treated with laser therapy, cryotherapy or corticosteroid injections. An excessively severe cyst can be surgically removed, along with the entire salivary gland. Depending on the severity, oral mucus cysts can take from one week to two years to heal completely.