Most sores on the lips clear up within 7 to 10 days, but the right treatment depends entirely on what type of sore you’re dealing with. The three most common culprits are cold sores (fluid-filled blisters on the outer lip border), canker sores (round white or yellow ulcers inside the mouth), and angular cheilitis (cracked, irritated skin at the corners of the mouth). Each has different causes and responds to different treatments.
Identify Which Type of Lip Sore You Have
Cold sores appear as clusters of small, fluid-filled blisters on or around the outer edge of your lips. They’re caused by herpes simplex virus type 1 (HSV-1), which lives in nerve cells and reactivates periodically. You’ll usually feel a tingling, itching, or burning sensation before the blisters show up. Over the next 48 hours, blisters form, then burst and crust into a scab. The whole cycle typically resolves within 10 days.
Canker sores look completely different. They’re single, round sores with a white or yellow center and a red border, and they only appear inside the mouth, on the inner cheeks, inner lips, or tongue. They don’t have a known single cause but can be triggered by mouth injuries, stress, smoking, or deficiencies in folic acid, iron, or vitamin B12.
Angular cheilitis shows up specifically at the corners of the mouth as red, cracked, crusty patches. Saliva pooling in the skin folds creates a moist environment where bacteria or fungi can take hold, turning a minor irritation into a persistent sore.
Treating Cold Sores
Antiviral treatment works best when you start at the first tingle, before blisters fully form. Over-the-counter topical antiviral cream (the active ingredient is docosanol or acyclovir) can modestly shorten healing time by roughly half a day when applied five times daily for four to five days. That’s not dramatic, but starting early makes the biggest difference.
Prescription oral antivirals are more effective. In clinical trials, a short course of valacyclovir reduced both healing time and pain duration by about half a day to a full day. Famciclovir performed even better in one study, cutting healing time by up to 2.2 days. If you get cold sores frequently, your doctor can prescribe a supply to keep on hand so you can start treatment the moment symptoms begin. For people with very frequent outbreaks, daily suppressive therapy is an option that significantly reduces recurrence.
While the sore heals, keep it clean and dry. Avoid picking at the scab, which delays healing and increases the risk of spreading the virus. Cold sores are contagious from the tingling stage until the scab falls off, so avoid kissing and sharing utensils during that window.
Lemon Balm for Cold Sores
Lemon balm (Melissa officinalis) extract has some promising evidence behind it. In a double-blind, placebo-controlled study of 66 people with recurrent cold sores, those using 1% lemon balm cream four times daily showed significant improvement by day two. Lab studies suggest compounds in lemon balm, particularly rosmarinic acid, interfere with the virus’s ability to attach to and enter cells. Look for lip balms or creams containing lemon balm extract as a complementary approach alongside conventional treatment.
Lysine Supplements
The amino acid lysine is one of the most commonly recommended supplements for cold sore prevention, though the evidence is mixed. Some studies found that taking 1,000 mg daily reduced the frequency and severity of outbreaks over six months. Higher doses of up to 3,000 mg per day are sometimes used during active outbreaks. Other studies, however, found no benefit compared to placebo. It’s worth trying if you get frequent cold sores, but don’t rely on it as your only strategy.
Treating Canker Sores
Most canker sores heal on their own within one to two weeks without treatment. To speed things along and manage pain, you can use an over-the-counter oral gel or paste designed for mouth ulcers. These typically contain a numbing agent that provides temporary relief and a protective barrier that shields the sore from further irritation while eating or drinking.
Rinsing with warm salt water (about half a teaspoon in a cup of warm water) several times a day helps keep the area clean and can reduce inflammation. Avoid acidic, spicy, or rough-textured foods that scrape against the sore. If you get canker sores repeatedly, it’s worth checking for nutritional deficiencies. Low levels of vitamin B12, iron, or folic acid are linked to recurrent mouth ulcers, and a simple blood test can identify whether supplementation might help.
Treating Angular Cheilitis
Angular cheilitis won’t resolve with regular lip balm because it’s often driven by a fungal or bacterial infection in the cracked skin. Over-the-counter antifungal cream (the same type used for athlete’s foot) applied to the corners of the mouth several times a day often clears mild cases within a week or two. If the cracks are inflamed and painful, a topical steroid cream can reduce swelling. For stubborn cases, a doctor may prescribe a combination antifungal-steroid ointment or oral antibiotics if bacteria are involved.
To prevent it from coming back, keep the corners of your mouth dry. Lip licking makes it worse by creating the moist environment fungi thrive in. Applying a thick barrier ointment like petroleum jelly before bed can protect the skin overnight.
Preventing Lip Sores From Coming Back
For cold sores, UV exposure is one of the most reliable triggers, and SPF lip balm is one of the most effective preventive measures available. The numbers are striking: in one study, 57.9% of participants developed cold sores with a placebo lip product, while only 5.25% did when using a lip protectant with SPF. Another study found recurrence dropped from 71% to just 3% when participants switched from placebo to SPF 15 lip balm. Wearing SPF lip balm daily, not just at the beach, is one of the simplest things you can do if you’re prone to outbreaks.
Other common cold sore triggers include stress, illness, fatigue, and hormonal changes. You can’t avoid all of these, but recognizing your personal pattern helps you keep antiviral medication ready for early treatment.
Check Your Lip Products for Allergens
Sometimes what looks like a recurring sore is actually an allergic reaction to something you’re putting on your lips. Contact dermatitis of the lips can cause redness, cracking, swelling, and small blisters that mimic other conditions. Common allergens hiding in lip balms and lipsticks include peppermint oil, balsam of Peru (a fragrance ingredient), lanolin, vitamin E (tocopherol), propolis (found in beeswax), and sunflower-derived compounds.
If your lip sores keep appearing in the same general area where you apply product, and they don’t follow the typical cold sore or canker sore pattern, try eliminating your lip products for two weeks. Switch to plain petroleum jelly and see if the problem resolves. If it does, reintroduce products one at a time to identify the culprit. A dermatologist can also run patch testing to pinpoint the specific allergen.