A canker sore under your tongue is a small, painful, round or oval-shaped ulcer with a white or yellow center and a red border. These sores develop inside the mouth, unlike cold sores, which appear on the lips.
How Canker Sores Develop
Canker sores, or aphthous ulcers, form when the thin tissue lining your mouth is damaged. The exact cause is unknown, but triggers include:
Minor injuries (biting your tongue, dental work)
Acidic or spicy foods
Toothpaste or mouthwash containing sodium lauryl sulfate
Helicobacter pylori infection (the same bacteria linked to stomach ulcers)
I once developed a canker sore after eating pineapple daily for a week. The acidity triggered a minor ulcer under my tongue that took about 10 days to heal. I switched to milder fruits and used a medicated mouth rinse to speed recovery.
When to See a Doctor
Most canker sores heal on their own. However, see a doctor if:
The sore lasts longer than 3 weeks
It's unusually large (larger than 1/3 inch)
You have frequent outbreaks (more than twice a year)
The sore is extremely painful or interferes with eating/drinking
You have other symptoms (fever, diarrhea, headache)
Treatment Options
For relief, try:
Over-the-counter numbing agents (like Orajel)
Antimicrobial mouth rinses (such as chlorhexidine)
