That painful bump inside your mouth is almost certainly not a pimple. Unlike skin pimples, which form when oil clogs a pore, the inside of your mouth doesn’t have oil-producing glands. What you’re dealing with is most likely a canker sore (a small, shallow ulcer) or a mucocele (a fluid-filled cyst caused by a blocked salivary gland). The good news: most of these resolve on their own within two weeks, and simple home remedies can speed things along and cut the pain.
Figure Out What You’re Dealing With
Canker sores are the most common culprit. They look like small, round or oval ulcers with a white or yellowish center and a red border. They typically appear on the inner cheeks, lips, tongue, or soft palate, and they hurt, sometimes a lot, especially when you eat or talk. Most are smaller than a centimeter.
Mucoceles look different. They’re dome-shaped, bluish or translucent bumps, usually on the inner lower lip. They form when a salivary gland gets damaged or blocked, often from accidentally biting your lip. Mucoceles are generally painless and feel soft or fluid-filled when you press on them. Small ones sometimes resolve on their own, but larger or persistent ones need professional treatment.
If the bump is hard, doesn’t hurt, sits on firm tissue like the gums or roof of the mouth, and has been there for more than two weeks, that’s a different situation entirely. A sore or growth that won’t heal, especially one with white or reddish patches, can be a sign of oral cancer and should be evaluated by a doctor or dentist promptly.
Home Remedies for Canker Sores
If you’re dealing with a canker sore, the goal is to reduce pain, keep the area clean, and let it heal. A saltwater rinse is the simplest option: dissolve half a teaspoon of salt in a cup of warm water and swish gently for 30 seconds, then spit. You can also use a baking soda rinse, which neutralizes acid in the mouth. The Mayo Clinic recommends dissolving 1 teaspoon of baking soda in half a cup of warm water. Repeat either rinse several times a day, especially after meals.
Over-the-counter numbing gels containing benzocaine can dull the pain enough to eat and drink comfortably. Apply the gel directly to the sore up to four times a day, and don’t use it for more than two consecutive days without checking with a doctor. Benzocaine products are not recommended for children under 2.
While the sore is healing, avoid spicy, acidic, or crunchy foods that scrape against it. Citrus fruits, tomato sauce, chips, and hot beverages are the usual offenders. Stick to softer, cooler foods when possible.
Why You Shouldn’t Pop a Mucocele
If the bump is a mucocele, resist the urge to pop or drain it yourself. Puncturing it at home can introduce bacteria and cause an infection, and it will almost certainly refill because the underlying blocked gland is still there. Very small, painless mucoceles sometimes disappear on their own over a few weeks.
For mucoceles that stick around, a dentist or oral surgeon can remove them using a few different methods. Surgical excision is the most common approach, where the cyst and sometimes the affected salivary gland are removed. Cryotherapy, which freezes and destroys the tissue, and laser treatment are less invasive alternatives that work well for smaller cysts. Recovery from these procedures is generally quick, with the area healing within a week or two.
When a Canker Sore Needs Professional Help
Most canker sores heal within two weeks without any treatment beyond basic home care. But some warrant a call to your dentist or doctor. Watch for sores that last longer than two weeks, are larger than a pea (about one centimeter), come with fever or flu-like symptoms, make it hard to eat or drink, or keep coming back two or three times a year.
For severe or recurring canker sores, dentists can prescribe topical anti-inflammatory pastes that reduce swelling and pain more effectively than over-the-counter options. These work by calming the immune response in the tissue around the ulcer. Laser treatment is another in-office option that can relieve pain almost immediately and speed healing.
Preventing Mouth Sores From Coming Back
If you get canker sores regularly, your toothpaste might be part of the problem. A systematic review of clinical trials found that toothpastes containing sodium lauryl sulfate (SLS), a foaming agent in most major brands, significantly increased the number of ulcers, the duration of each episode, and the level of pain compared to SLS-free alternatives. Switching to an SLS-free toothpaste is one of the simplest changes you can make. Several brands market themselves as SLS-free, and you can find them at most drugstores.
Nutritional deficiencies also play a role. Vitamin B12 deficiency is linked to recurrent mouth ulcers, along with a burning sensation on the tongue and cracked corners of the lips. Iron deficiency can cause similar problems. If your sores keep returning despite good oral hygiene, it’s worth asking your doctor to check your B12 and iron levels with a simple blood test. Correcting a deficiency often reduces or eliminates the recurrence.
Other common triggers include stress, hormonal changes, accidentally biting the inside of your cheek, and rough dental work that rubs against soft tissue. Braces and ill-fitting dentures are frequent offenders. If a specific spot in your mouth keeps getting irritated, your dentist can smooth or adjust the source of the friction.