Bump on the Inside of Your Lip: What It Is and When to See a Doctor

What does it look like?

When to see a dentist or doctor

See a dentist or GP if:

• a mouth ulcer lasts longer than 3 weeks;
• an ulcer is different from ones you've had before, for example bigger than usual or near the back of your throat;
• an ulcer bleeds or becomes more painful and red, which may be a sign of infection;
• you have a lump inside your mouth or on your lip, or a lump in your neck or throat;
• you have a red or white patch in your mouth;
• you have pain in your mouth that doesn't go away, difficulty swallowing or speaking, or a hoarse voice that doesn't go away.

A dentist can also check ulcers, lumps, patches and mouth pain. These symptoms are very common and can be caused by other conditions; having them doesn't mean you have mouth cancer, but they should be checked, because finding cancer early may make it easier to treat (NHS).

Get urgent help if a swelling under the tongue makes breathing difficult. MedlinePlus notes that a ranula growing into the neck can narrow the airway, which is a medical emergency.

Don't try to open a mucocele yourself. It can lead to infection and tissue damage (MedlinePlus). Many mucoceles rupture on their own. One that keeps returning can be removed by an oral surgeon or dentist with surgery, laser or freezing (cryotherapy).

Sources: NHS, "Mouth ulcers" and "Symptoms of mouth cancer"; MedlinePlus, "Oral mucous cyst"; DermNet, "Mucocoele of the lip."

What is a bump on the inside of your lip?

A bump on the inner lip is a very common reason patients see dentists and dermatologists. The inside of the lip has minor salivary glands, mucosa, and connective tissue — all of which can produce small, mostly benign lesions in response to trauma, inflammation, or infection. The pattern, color, firmness, and timeline of the bump usually tell the diagnosis.

Mucoceles (mucous cysts)

A common cause, especially on the inner lower lip. A mucocele forms when a minor salivary gland duct is blocked or ruptured — often after a lip bite. They appear as soft, bluish, dome-shaped bumps, typically on the lower lip. They're usually painless and up to about 1 cm across (MedlinePlus). Many resolve on their own within a few weeks; persistent or recurring mucoceles are usually treated with simple surgical excision or laser removal.

Canker sores (aphthous ulcers)

Painful, round or oval ulcers with a white or yellow center and a red rim. Triggers include stress, minor trauma, certain toothpastes (SLS), and nutritional deficiencies. Most heal in 7–14 days. Recurrent or unusually large canker sores warrant a workup for nutritional or systemic causes.

Oral fibromas

A firm, painless, smooth bump caused by repeated trauma — most often habitual lip or cheek biting. Fibromas tend to persist; a dentist or oral surgeon can remove one in the office if it bothers you.

Oral mucosal cysts and ranulas

Larger cysts can develop on the floor of the mouth (ranulas) or elsewhere in the oral mucosa. They are usually painless but can interfere with speech, eating, or comfort. Treatment is surgical, often with marsupialization or excision.

HPV-related bumps (oral papillomas)

Oral papillomas are small, cauliflower-like or finger-shaped growths associated with low-risk strains of HPV. They are usually painless and treated with surgical or laser removal. A persistent oral lesion that doesn't fit the pattern of any benign cause should always be evaluated to rule out an HPV-associated or other neoplastic process.

Less common causes

• Oral lichen planus — chronic inflammatory condition with white lacy patches or erosions
• Salivary gland tumors — rare; firm, slowly growing, painless masses
• Lipomas — soft, painless fatty growths
• Pyogenic granuloma — rapidly growing red bump that bleeds easily, often after trauma or in pregnancy

Treatment options

Observation is appropriate for many bumps that are clearly benign and likely to resolve. Persistent or recurring lesions are typically treated with simple excision, laser removal, or — when there is any uncertainty — biopsy. A dentist, oral medicine specialist, or oral and maxillofacial surgeon can usually evaluate and treat in a single visit.

Haute MD dentists

• Dr. Husam Almunajed, cosmetic and restorative dentist, New York
• Dr. Mimi Yeung, general and cosmetic dentist, New York

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This article is educational and does not replace evaluation by a qualified clinician. Any oral lesion that fails to heal in 3 weeks should be examined in person.

Frequently Asked Questions