How to Treat Cold Sores Inside Your Mouth

Relieving Pain and Swelling

Use a cold compress on your lips. Wrap an ice pack or frozen bag of peas in a cloth or paper towel and place it over your lips or cheek. The cold will numb the pain from the sore and make it easier to eat and drink. Use a cold compress as needed, whenever your sore feels painful. If the sore is on your tongue or the roof of your mouth, place ice cubes into your mouth one at a time and allow them to melt slowly.

Rinse your mouth with baking soda, salt, and warm water. Mix 1 tablespoon (14.8 ml) (17 g) of salt and 1 tablespoon (14.8 ml) (14 g) of baking soda into 4 fluid ounces (120 mL) of warm water. Gargle with the mixture for 1-2 minutes, then spit it out. Do not swallow the mixture. Use this treatment for 4 days, or until your sore stops hurting. You can use this mixture up to 4 times a day to relieve pain.

Place a drop of milk of magnesia on your sore up to 3 times a day. Use a clean finger to apply a drop of milk of magnesia onto the sore and the area around it. Milk of magnesia is available over the counter at pharmacies. Apply milk of magnesia 3 times daily until the sore stops hurting, usually in around 3-4 days.

Place a soaked tea bag over the infected area for 5 minutes. Black or green tea is alkaline and contains astringent compounds that can relieve pain. Make yourself a cup of tea in hot water and then place the warm tea bag onto your lip, cheek, or gum where the sore is. Use this treatment as needed whenever your sore feels painful. The heat from the tea bag can also numb pain.

Use aloe vera to relieve pain. The gel from the aloe vera plant is a natural pain reliever. Break open a leaf of an aloe vera plant and squeeze the gel directly out, then use a cotton bud to apply it to your sore. You can use a drop of aloe vera gel around 4 times a day, after meals and before bed. Alternatively, you can drink aloe vera juice to get a similar effect. Consuming aloe vera can cause stomach aches and diarrhea with long-term use at high doses. Only use it for 3-4 days when your sore is most painful and stop when it starts to feel better to avoid risk.

Rinse your mouth with an antiseptic mouth sore wash. To kill any bacteria that may be irritating your sore, swish a capful of antiseptic mouthwash around for a minute and then spit it out. Use the mouthwash after meals and before bed for the best results. Stop using the mouthwash once your sore stops hurting, after around 4 days. This can potentially help your sore heal faster, and will relieve pain in the meantime. These mouthwashes are available over the counter at most pharmacies.

Use over the counter acetaminophen or oral lidocaine to help reduce pain. Take acetaminophen when you feel pain and wait for about 15–30 minutes for it to start taking effect. You can take additional acetaminophen after 6 hours if you still have pain. If you use oral lidocaine, place a bead-sized amount on the end of a cotton swab and apply it directly to the canker sore. Use lidocaine once every 3 hours if you need to apply more. You can buy oral lidocaine and acetaminophen from your local pharmacy or drugstore.

Preventing Further Irritation

Avoid acidic and spicy foods. Foods high in acid and spice will aggravate the sore and make it feel more painful. Eat soft, bland foods, especially during the first 3-4 days of your infection. After that, the sore will start to heal and won't be as painful. Good choices of non-acidic foods include yogurt, potatoes, non-citrus fruits, and whole-grain pasta.

Drink cool, non-acidic beverages. Acidic drinks such as orange juice and lemonade and hot drinks like coffee and tea can irritate a canker sore and make it heal more slowly. Good choices for beverages include cool water and milk and iced tea. Drinking through a straw can also help if you are still experiencing pain.

Stop chewing gum for at least 3-4 days. Chewing gum contains ingredients that can irritate your sore and make it heal more slowly. Avoid it until your sore stops hurting, for at least 3-4 days. Your sore will continue to heal but won't hurt after a few days. It's safe to start chewing gum again when the sore stops hurting.

Avoid crispy and crunchy foods. The texture of hard, crunchy foods can rub up against your sore and make it more painful. This includes foods like chips, toast, and bread with crispy crusts. Wait until your sore stops hurting to eat crunchy foods. Some good options include cereal that has been soaked in milk, soft-shell tacos, mashed potatoes, pasta, and rice. Try cooked vegetables and fruit cups for softer fruit and vegetable options.

Brush your teeth gently. Aggressively brushing your teeth can irritate the sore and make it hurt more. Use a soft-bristled toothbrush and use light pressure around the area where the sore is. A foaming-agent-free toothpaste can also reduce irritation. These kinds of toothpaste can be found over the counter at most pharmacies.

Seeking Medical Attention

See your doctor if you get recurring sores inside your mouth. One or two sores is nothing to worry about, but if you get sores frequently, it can be a sign of a larger problem. Sometimes, canker sores can be a sign of gluten intolerance or a vitamin B12 deficiency. Most cold sores go away on their own, so if they don't, then that's a sign that something else is wrong.

Make an appointment with your doctor if the sore doesn't go away in a week. Most cold and canker sores go away within 7-10 days. If yours doesn't, see your doctor to have it checked out. You may need a medicated balm or other treatment to help it go away.

Change your diet if your doctor recommends it. You may get sores inside your mouth as a result of celiac disease. Other causes could be vitamin or mineral deficiencies, usually vitamin B12 or iron. Your doctor may recommend something as simple as taking a dietary supplement. Or, you may need to make a major change like removing gluten from your diet entirely.

Use a steroid mouthwash for stubborn canker sores. Your doctor may prescribe the steroid dexamethasone to use as a mouthwash to reduce pain and inflammation or lidocaine for pain. These mouthwashes are typically prescribed for large and painful or persistent infections. Alternatively, your doctor may prescribe a gel or cream containing similar ingredients that you can apply directly to the sore.

Tell your doctor if a severe canker sore doesn't respond to treatment. If you have tried treating a canker sore at home and with medication and the sore is still painful after a week, follow up with your doctor. You may need a more intensive treatment or a different diagnosis. The next step might be a steroid injection, but since this can cause severe side effects, it is usually considered a last resort. Another option is cauterizing the sore, using an instrument to burn or destroy the infected tissue.