Most bumps on the inside of the lip are harmless. The most common causes are mucoceles (fluid-filled cysts from minor trauma), Fordyce spots (normal oil glands), canker sores, and small fibromas from habitual lip biting. In rare cases, a bump that persists longer than two weeks without changing can signal something that needs professional evaluation.
Mucoceles: The Most Common Culprit
If you have a soft, dome-shaped, fluid-filled bump on the inside of your lower lip, it’s most likely a mucocele. These form when a tiny salivary gland gets damaged or its duct gets blocked, usually from accidentally biting your lip, a minor injury, or even a habit of sucking your lip against your teeth. Saliva builds up with nowhere to go and forms a small cyst.
Mucoceles range from about 1 millimeter to 2 centimeters wide. They’re typically painless, bluish or translucent, and feel like a small balloon under the skin. The inner surface of the lower lip is by far the most common location. Many mucoceles rupture on their own and heal without treatment, but they often come back. If one keeps recurring or is large enough to bother you, a dentist or oral surgeon can remove it with a simple in-office procedure.
Fordyce Spots: Tiny, Painless, and Normal
If you’re noticing multiple small, pale or yellowish dots clustered along the inside of your lips, you’re almost certainly looking at Fordyce spots. These are slightly enlarged oil glands sitting in skin that doesn’t have hair follicles. They’re completely normal, not contagious, and not caused by any disease.
Between 70% and 80% of adults have them. They’re often present from birth but become more noticeable during puberty and adulthood as hormone levels change. Each spot is typically 1 to 3 millimeters, raised just slightly, and painless. They don’t require any treatment. Most people simply never noticed them before and become alarmed when they finally do, often while examining their mouth in good lighting.
Canker Sores
Canker sores are painful white or yellow ulcers with a red border that form exclusively inside the mouth, including on the inner lips, cheeks, and tongue. They’re not the same as cold sores, which appear on the outside of the lips and are caused by a virus. Canker sores are not contagious.
Minor canker sores, the most common type, are usually under 10 millimeters across, and most people get one to five at a time. They heal on their own within 10 to 14 days. Major canker sores are larger than 10 millimeters and can persist for up to six weeks, sometimes leaving a scar. Triggers include stress, acidic or spicy foods, minor mouth injuries, and nutritional deficiencies. Over-the-counter topical gels can reduce pain while they heal.
Fibromas From Lip or Cheek Biting
If you have a firm, painless, rounded bump that matches the color of the surrounding tissue, it could be an irritation fibroma. These develop as a response to repeated trauma like chronic lip biting, cheek chewing, or rubbing from braces or dental appliances. The body essentially builds a small knot of fibrous tissue at the site of irritation.
Fibromas are dome-shaped, smooth, and usually the same pinkish color as the rest of your inner lip, though they can appear lighter or darker if there’s been bleeding underneath. They don’t go away on their own because the extra tissue is permanent. If one bothers you or keeps getting bitten, a dentist can remove it quickly. They rarely come back after removal unless the source of irritation continues.
Oral Papillomas
A bump with a rough, cauliflower-like or finger-like texture on the surface is likely a squamous papilloma. These benign growths are linked to certain strains of human papillomavirus (HPV) and are usually painless, slow-growing, and the same color as the surrounding tissue or slightly whiter. They’re typically attached to the tissue by a narrow stalk.
Papillomas don’t become cancerous, but they won’t resolve without removal. A dentist or oral surgeon can excise one easily, and recurrence is uncommon.
Blocked Salivary Gland Ducts
Your lips contain hundreds of tiny salivary glands, and occasionally a small stone can form inside one of their ducts and block saliva flow. When this happens, the gland swells, becomes tender, and can feel like a firm, painful bump. The swelling may get worse around mealtimes when saliva production increases.
A blocked duct differs from a mucocele in that it tends to be more painful and may become infected if the blockage isn’t cleared. Treatment usually involves numbing the area and gently opening the duct to remove the stone.
When a Bump Needs Professional Attention
Most inner lip bumps are benign, but certain features should prompt a visit to your dentist. A sore or lump that doesn’t heal within two weeks is the most important warning sign. Other red flags include a white or reddish patch that won’t go away, a growth that bleeds easily, numbness in the area, unexplained pain, or a lump that keeps getting bigger.
Oral cancers can appear as persistent sores, lumps, or patches inside the mouth. They’re uncommon on the inner lip compared to other oral sites, but they do occur. A dentist will inspect the area visually and, if anything looks abnormal, take a small tissue sample to test. Early detection makes a significant difference in outcomes.
A dentist is the right first stop for any bump inside your mouth. They examine oral tissue routinely and can distinguish between common harmless lesions and anything that warrants a biopsy or referral to a specialist.