A sore inside the cheek or a small bump in the mouth is something most people notice at some point. Many are caused by minor injury and heal within a week or two. Others, such as a bump on the gum near a tooth, can be a sign that a tooth needs attention. Here are the most common causes.
Common causes of sores inside the cheek and mouth
- Cheek biting or injury – biting your cheek while eating, a sharp tooth edge, braces or a hard toothbrush can leave a sore or white patch.
- Mouth ulcers – round, white or yellow sores with a red border. See our guide to mouth ulcers.
- Burns – hot food or drinks can leave a raw, peeling area, often on the roof of the mouth.
- Mucocele – a soft, comfort-focused, fluid-filled bump, usually on the inside of the lower lip, caused by a blocked or damaged saliva gland.
- Fibroma – a firm, smooth lump that can form where the cheek is repeatedly bitten.
- Oral thrush – creamy white patches that may wipe off, leaving a red area. It is more common in denture wearers, people using steroid inhalers and people with dry mouth.
- Linea alba – a harmless white line along the inside of the cheek where the teeth meet.
Can you get a pimple inside your mouth?
The mouth does not get pimples in the same way skin does, but several things can look like one. A small bump on the gum next to a tooth that releases pus or a bad taste is often a gum boil (dental abscess). It usually means there is an infection in the tooth or gum and it will not go away on its own, even if it stops hurting. This needs to be seen by a dentist, and treatment may include root canal treatment or treating the gum.
Red bumps inside the cheek can also be irritated saliva glands, a reaction to food or toothpaste, or a viral infection.
What you can do at home
- Rinse with warm salty water a few times a day.
- Avoid spicy, acidic and very hot food until it settles.
- Brush gently with a soft toothbrush.
- Check for anything rubbing the area, such as a sharp tooth or a loose denture.
When to get a sore in your mouth checked
- It has not healed after two to three weeks
- There is a lump that is growing or feels firm
- A bump on the gum near a tooth, or a bad taste or pus
- A white or red patch that does not wipe off
- Numbness, bleeding or difficulty swallowing
Your dentist checks the soft tissues of your mouth at every check-up, which is one of the best ways to pick up changes early. Learn more about mouth cancer signs.
Frequently asked questions
What causes a sore on the gum next to a tooth?
A sore or small bump on the gum beside a tooth can be an ulcer, irritation from food or brushing, or a gum boil from a tooth infection. A gum boil that keeps coming back or leaks fluid should be checked by a dentist promptly.
Why do I have a sore on the roof of my mouth?
Common causes include burns from hot food or drinks, scratches from hard foods, mouth ulcers and irritation from dentures. Most heal within 7–10 days. A sore that lasts longer than two weeks should be checked.
What causes sores at the back of the mouth?
Sores at the back of the mouth or throat are often linked to viral infections, ulcers or irritation. See your GP or dentist if you also have fever, trouble swallowing, or the sore lasts more than two weeks.
When should a mouth sore be checked?
Any mouth sore that hasn’t healed within two weeks, keeps coming back, is very painful, or bleeds easily should be checked by a dentist or doctor.
Not sure what that sore is?
If something in your mouth is not healing or you are unsure what it is, the team at Penrith Dental Care can take a look. Call (02) 4733 1197 or book an appointment online.
For more general health information, see healthdirect: oral thrush.
Related reading
- Mouth Ulcers: Causes, Home Remedies and When to See a Dentist
- Bad Taste in Mouth: Common Causes
- Emergency Dentist Penrith
- Mouth cancer: signs, symptoms and when to get checked
Looking for more dental health tips? Browse all articles on the Penrith Dental Care blog, or meet the Penrith Dental Care team. Have a question? See our dental FAQ.
This article is general information and does not replace advice from your own dental practitioner.