What is this bump under my tongue?

Lift your tongue in a mirror and you will see a thin web of tissue in the middle (the frenulum), shiny, thin lining, and bluish veins running toward the tip. On either side of the frenulum, on the floor of the mouth, are the openings where saliva glands empty. All of this is normal.

The veins under the tongue often become wider, darker and more knotted with age. These are called sublingual varices. A 2024 systematic review describes them as a variation of normal that becomes more prominent with aging, and found them more often in people with high blood pressure, diabetes, smoking, or varicose veins in the legs. They are not dangerous by themselves, but they can be a nudge to keep up with blood pressure checks.

• Mucocele (mucus cyst). MedlinePlus describes a painless, thin sac of clear fluid that is often clear, bluish or pink, soft and dome-shaped, up to about 1 cm across. The underside of the tongue is a common site. Most follow a bite or other small injury that damages a tiny saliva gland.
• Ranula. A mucus cyst on the floor of the mouth from a larger saliva gland. Cleveland Clinic describes a clear or bluish, squishy lump under the tongue that can grow and shrink as saliva collects and drains. A "plunging" ranula can extend down into the neck.
• Salivary gland stone. The NHS notes that most salivary stones form below the tongue. They are hard and white when visible, and typically cause swelling and pain that flare up at mealtimes, when saliva flow increases.
• Canker sore. Cleveland Clinic lists the underside of the tongue as a common place for these shallow, painful ulcers with a white or yellow base and a red rim.
• A bite or scrape. Sharp food, a broken tooth or a dental instrument can leave a tender swollen spot that heals within a week or two.

• Squamous papilloma. A small growth with finger-like projections, linked to low-risk HPV types. An AAFP photo quiz notes these are the most common benign oral tumors and favor the underside of the tongue. They are removed and checked.
• Lymphoepithelial cyst. The AAFP describes small yellowish nodules on the underside of the tongue or floor of the mouth. They are benign, but a biopsy is needed to confirm.
• Erythroplakia or leukoplakia. A red or white patch that does not wipe off. Cleveland Clinic notes erythroplakia often appears under the tongue or behind the lower front teeth and is usually precancerous or cancerous, so it always needs a biopsy.
• Mouth cancer. NIDCR lists under the tongue among the places oral cancer develops, and the AAFP notes oral cancers most commonly involve the tongue and the floor of the mouth. Early cancer can look like a small ulcer or patch rather than a big lump.

• Do not try to pop or drain it. MedlinePlus and Cleveland Clinic both warn that opening a mucus cyst yourself risks infection and tissue damage. Never use anything sharp on a suspected salivary stone either.
• For a suspected stone, the NHS suggests drinking plenty of water, sucking sugar-free sweets or chewing sugar-free gum to boost saliva, and gently massaging around the area.
• For an ulcer or bite, rinse with warm salt water and avoid spicy, salty and acidic food until it heals.
• Stop biting or sucking the area if you have a habit of it, since this is how many mucoceles start.
• Note the date. If it is still there after 2 to 3 weeks, or keeps coming back, book a dental visit.

Many mucoceles burst and heal on their own. If one keeps returning, it can be removed by surgery, laser or freezing, often along with the small gland feeding it. Ranulas may be drained, opened so they keep draining, or removed with the gland, which Cleveland Clinic calls the only permanent fix. Salivary stones can sometimes be eased out with a blunt instrument; larger ones are removed in hospital. Any solid growth or lasting patch is usually biopsied so it can be identified with certainty.