Most sores under the tongue are canker sores, and they heal on their own within one to two weeks. You can speed up that timeline and reduce pain with saltwater rinses, over-the-counter numbing gels, and a few simple habit changes. The key is identifying what kind of sore you’re dealing with, because the treatment depends on the cause.
What’s Causing the Sore
The area under your tongue is lined with soft, non-keratinized tissue, which means it lacks the tougher protective layer found on your gums or the roof of your mouth. That makes it one of the most common spots for canker sores (aphthous ulcers) to develop. About 20% of the general population gets canker sores, and the floor of the mouth is a frequent location.
The most common triggers include biting the inside of your mouth, irritation from a sharp tooth edge or dental work, stress, and nutritional deficiencies, particularly low levels of iron, vitamin B12, or folic acid. Many people also report a family history of canker sores, suggesting a genetic component. Sometimes just switching toothpaste brands or eating acidic foods like tomatoes or citrus is enough to set one off.
Not every sore under the tongue is a canker sore, though. A smooth, round, fluid-filled bump is more likely a mucocele, which forms when a minor salivary gland duct gets blocked or damaged. These are painless or mildly uncomfortable and feel like a small blister. A painful lump that swells during meals and then subsides could be a salivary stone blocking one of the ducts under your tongue. Salivary stones often cause a bitter taste, difficulty swallowing, and pain that flares when you eat and fades between meals.
Home Remedies That Work
Saltwater rinses are the simplest and most effective first step. Mix one teaspoon of salt into eight ounces of warm water (cut to half a teaspoon if it stings too much). Swish it around your mouth for 15 to 20 seconds, then spit. You can repeat this several times a day, especially after eating, to keep the area clean and reduce bacteria. Salt draws fluid out of the tissue, which helps shrink swelling and promotes healing.
Honey applied directly to the sore is another option with real evidence behind it. A 2025 meta-analysis of 25 randomized controlled trials found that thyme honey was actually more effective than the standard prescription steroid paste at reducing pain and ulcer size. Dab a small amount of raw honey onto the sore a few times a day. It forms a protective coating and has natural antibacterial properties.
Other things that help during healing:
- Avoid irritating foods. Spicy, acidic, salty, and crunchy foods all aggravate open sores. Stick to softer, blander foods until the sore closes.
- Switch toothpaste. Toothpastes containing sodium lauryl sulfate (SLS) can trigger or worsen canker sores. Look for an SLS-free option.
- Use a soft-bristled toothbrush. Hard brushing near the sore slows healing and can cause new ulcers at trauma sites.
Over-the-Counter Treatments
If the pain is interfering with eating or talking, a numbing gel containing benzocaine gives fast temporary relief. Apply it directly to the sore up to four times a day. Don’t use it for more than two consecutive days without checking with a pharmacist or doctor, and avoid it entirely for children under two. These products come as gels, liquids, and sprays, and you’ll find them in most pharmacy oral care sections.
Protective paste products that form a barrier over the sore can also help. They shield the ulcer from contact with food, teeth, and your tongue, which reduces pain and gives the tissue a chance to heal without repeated irritation. Look for products marketed specifically as oral wound care or canker sore patches.
When You Might Need a Prescription
For canker sores that are large, unusually painful, or keep coming back, a doctor or dentist can prescribe a topical steroid paste. The most commonly used option is applied directly to the sore four times daily. For severe or widespread ulcers, higher-potency formulations may be held over the lesion with a small piece of gauze. These treatments reduce inflammation and can cut healing time significantly.
If your sore turns out to be a salivary stone, treatment depends on the stone’s size. Small stones sometimes pass on their own with increased hydration, warm compresses, and gentle massage of the area. Sucking on sour candies stimulates saliva flow and can help push a small stone through the duct. Larger stones that cause intense pain or recurring blockages typically need to be removed by a doctor.
Mucoceles that don’t resolve on their own within a few weeks are usually removed with a minor in-office procedure. They tend to recur if the damaged gland isn’t fully addressed.
Check Your Nutrition
Recurring sores under the tongue can signal a nutritional gap. Iron deficiency, low vitamin B12, low folic acid, and insufficient vitamin C have all been linked to recurrent canker sores. B12 deficiency in particular is associated with changes in the cells lining the tongue and the floor of the mouth, which may make those tissues more vulnerable to ulceration.
If you get canker sores frequently, it’s worth asking your doctor to check your levels. A simple blood test can identify deficiencies, and correcting them with diet or supplements often reduces how often sores come back. Good dietary sources of B12 include meat, fish, eggs, and dairy. Iron-rich foods include red meat, lentils, and spinach.
Signs a Sore Needs Medical Attention
A standard canker sore should show clear improvement within a week and be fully healed within two. If a sore under your tongue lasts longer than two weeks, that’s the clearest signal to get it evaluated by a doctor or dentist. Other warning signs include bleeding from the sore that doesn’t stop, any texture change like rough patches, cracking, or crustiness, a lump or thickening that doesn’t go away, or difficulty swallowing that persists.
These features don’t automatically mean something serious, but a sore that won’t heal is one of the ways oral cancers first appear, and early evaluation makes a significant difference in outcomes. A quick visual exam, and occasionally a biopsy, is all it takes to rule it out.