Pain under your tongue is common and usually comes from irritation, minor injury, or infection, but it can sometimes signal something more serious that needs prompt dental or medical care.

Most common reasons your tongue hurts underneath

  • Accidental bite or trauma : Chewing fast, talking while eating, sports injuries, or even grinding your teeth can cause a small cut or bruise under the tongue that then feels very sore for several days.
  • Burns or food irritation : Very hot drinks/foods or spicy/acidic foods can burn or irritate the delicate tissue under your tongue, leading to redness, swelling, and a burning sensation.
  • Sores or canker ulcers : A single painful spot that started as tingling, then turned into a round white, yellow, or red sore may be a canker sore (aphthous ulcer), often triggered by minor trauma, stress, or sensitivity to certain foods or toothpaste.
  • Irritation from teeth or dental work : Sharp or broken teeth, braces, retainers, dentures, or rough fillings can constantly rub the underside of your tongue and create sore spots or cuts.
  • Infections :
    • Fungal infection (oral thrush) can cause white patches and soreness.
* Bacterial or viral infections (like mumps or other oral infections) can inflame glands and tissues under the tongue, causing pain and swelling.
  • Inflamed salivary glands / blocked duct : The glands under your tongue can get inflamed or blocked (for example by a small stone), causing a tender lump or swelling and pain, especially when you eat and saliva flow increases.
  • Glossitis (inflamed tongue) : Inflammation of the tongue from allergies, low iron, trauma, dental appliances, or other conditions can cause diffuse soreness, sometimes affecting the underside as well.
  • Allergic or sensitivity reaction : New toothpaste, mouthwash, medications, or foods can trigger irritation and soreness of the tongue and mouth tissues.
  • Less common but serious causes : Long‑lasting pain, a non‑healing sore, a firm lump, or changes in color/texture of the area under your tongue can very rarely be linked to conditions like oral cancer or autoimmune diseases, and these need a prompt professional check.

What to watch for right now

Pay close attention to:

  • How long it has hurt (hours vs weeks).
  • Whether you see a clear sore, cut, burn, blister, or white patch.
  • If there is swelling on one side, a lump, or trouble moving your tongue.
  • Triggers: started after biting your tongue, eating something hot or spicy, getting new braces/dentures, or starting a new medication or mouth product.

Home care that is usually safe (not a diagnosis)

If your pain is mild and recent, and you do not have severe symptoms, people are often advised to try:

  1. Rinsing gently with warm salt water a few times a day to keep the area clean and reduce irritation.
  1. Avoiding hot, spicy, acidic, or crunchy foods and alcohol/tobacco until it calms down.
  1. Using a soft‑bristle toothbrush and non‑irritating toothpaste (sometimes changing toothpaste helps if you’re sensitive).
  1. Avoiding playing with the sore area with your tongue or teeth so it can heal.
  1. Over‑the‑counter oral gels or pain relievers may be used short term if you’ve safely used them before and don’t have medical reasons to avoid them.

These steps are only for short‑term relief; they don’t replace an exam.

When to see a dentist or doctor urgently

You should seek urgent in‑person care (same day or emergency) if:

  • The area under your tongue is very swollen , making it hard to breathe, swallow, or move your tongue.
  • Pain is severe and rapidly worsening.
  • You have fever, feel very unwell, or see spreading redness in the mouth or neck.
  • There is sudden, marked swelling under your tongue or jaw (could be an infected or blocked salivary gland or other serious infection).

You should book an appointment soon (within days) if:

  • Pain under your tongue lasts more than 1–2 weeks.
  • A sore under your tongue keeps coming back or never fully heals.
  • You notice a firm lump, persistent white or red patch, or unexplained bleeding.
  • You recently got new dental work, braces, or dentures and the area keeps rubbing and hurting.

Quick example to help you compare

  • If you bit your tongue yesterday, now have a small visible cut that’s sore but improving with salt‑water rinses, that often fits minor trauma that heals in about a week.
  • If you’ve had a painful spot under your tongue for over two weeks with no clear injury, or it’s getting bigger or harder, that’s a reason to have a dentist or doctor examine it in person.

If you tell me how long it has hurt, whether you see a sore, lump, or white patch, and if you had any recent bites, burns, or dental work, I can help you think through which causes are more likely and what to ask your dentist or doctor.