A small cut at the corner of your mouth typically heals within a few days if you keep it clean, dry, and protected with a barrier ointment like petroleum jelly. The challenge with this spot is that every time you eat, talk, yawn, or lick your lips, the wound reopens. That constant movement is why corner-of-mouth cuts are notoriously slow healers and why they sometimes turn into a longer-lasting condition called angular cheilitis.
Why This Spot Heals So Slowly
The corners of your mouth are a hinge point. They stretch dozens of times an hour, which tears apart the fragile new skin trying to close the wound. Saliva also pools naturally in these creases, and moisture softens the surrounding skin (a process called maceration), making it even more prone to cracking. If you tend to lick the area because it feels dry or irritated, you’re actually making the problem worse: saliva evaporates quickly, leaving the skin drier than before and restarting the cycle.
Simple Cut vs. Angular Cheilitis
A one-time cut from biting into a hard piece of bread or stretching your mouth too wide at the dentist is straightforward. It hurts, it scabs, it heals. Angular cheilitis is different. It’s a persistent cracking at the mouth corners where bacteria or fungi have moved into the broken skin and set up an infection. Symptoms include redness, swelling, crusting, bleeding, blistering, and skin that looks soggy or lighter-colored around the crack.
The simplest way to tell the difference: if your cut hasn’t improved after a week of good home care, or if both corners of your mouth are affected at the same time, you’re likely dealing with angular cheilitis rather than a simple wound.
How to Heal a Simple Corner Cut
The goal is to protect the wound from moisture and movement while giving new skin a chance to form. Here’s what works:
- Apply a barrier ointment. Petroleum jelly (Vaseline) or Aquaphor creates a waterproof seal that keeps saliva out of the crack and locks moisture into the skin itself. Reapply after eating, drinking, and brushing your teeth. A thin layer before bed is especially helpful since you can’t control drooling while you sleep.
- Stop licking the area. This is the single most important habit to break. Every time your tongue touches the corner, it deposits saliva that softens the wound edges. When you feel the urge, apply ointment instead.
- Minimize how wide you open your mouth. For a few days, cut food into smaller pieces, avoid oversized sandwiches, and try not to yawn with your mouth wide open. Less stretching means less re-tearing.
- Keep the area clean. Gently wash with lukewarm water and pat dry before applying ointment. Avoid mouthwashes or toothpaste that might irritate the skin around the corners.
Most simple cuts heal within 3 to 5 days with consistent ointment use. If you keep pulling the wound open during meals, it can take a week or more.
When It Becomes Infected
If the crack gets red, swollen, or crusty, or if you notice yellowish discharge, an infection has likely developed. The most common culprit is a yeast called Candida, the same fungus behind oral thrush. Bacteria can also colonize the area, sometimes alongside the fungus.
For mild infections, an over-the-counter antifungal cream often does the job. Clotrimazole (sold as Lotrimin), miconazole (Monistat), and terbinafine (Lamisil) all work. Apply a thin layer to the corners twice a day, and use petroleum jelly or Aquaphor between applications as a protective barrier. Most cases improve within one to two weeks.
If over-the-counter treatment doesn’t help, a doctor can prescribe a combination antifungal and mild steroid cream, which tackles both the infection and the inflammation at the same time. These prescriptions are typically used for two weeks and then stopped.
Nutritional Deficiencies That Cause Recurring Cracks
If your mouth corners crack repeatedly without an obvious injury, a vitamin or mineral deficiency may be the underlying cause. Nutritional deficiencies account for about 25% of all angular cheilitis cases. The most common ones are iron deficiency and low levels of several B vitamins: riboflavin (B2), niacin (B3), pyridoxine (B6), and B12.
Iron deficiency is especially worth considering if you also feel unusually tired, look pale, or get short of breath easily. In documented cases, supplementing iron resolved the cracking completely. B vitamin deficiencies tend to show up alongside other symptoms like a sore or swollen tongue, fatigue, or numbness and tingling in the hands and feet.
If you’re dealing with cracks that keep coming back every few weeks, a simple blood test can check your iron and B vitamin levels. Correcting the deficiency often stops the cycle for good.
Habits That Prevent It From Coming Back
Once you’ve healed a corner crack, a few small changes can keep it from returning. Use a lip balm or petroleum jelly before bed every night, especially in dry or cold weather. Stay hydrated, since chronic mild dehydration dries out skin and mucous membranes. If you wear dentures, make sure they fit properly, as ill-fitting dentures change how saliva flows around your mouth and create deeper skin folds at the corners where moisture collects.
Limiting very acidic or sugary foods can also help if you tend to produce excess saliva, since both increase saliva output and keep the corners of your mouth wetter than they need to be. And if you catch yourself licking your lips out of habit, switching to a flavored lip balm you actually enjoy using can make it easier to reach for the balm instead of your tongue.