Sore, red, chapped lips can crack open when you eat, drink, talk and smile. Blisters on the lips can make the problem even more painful. Although you can treat and prevent most cases of chapped and blistered lips through home care, mouth sores and irritation can sometimes indicate underlying medical conditions, tumors or allergic reactions. See your doctor if the blisters last longer than two weeks or if you experience other symptoms, such as fever, difficulty swallowing, drooling or skin rashes.
Exposure to the sun and dry, cold winter air can cause lips to crack, peel and blister. Biting at your lips or licking them in an attempt to soothe their dryness can worsen the condition. Cold sores -- fluid-filled lesions on the mouth caused by the herpes simplex virus -- can cause blisters on your lips, as well as chapping and irritation.
Chapped lips and blisters caused by dehydration usually start out with mild irritation or redness and worsen over time if you fail to remedy the conditions causing the dryness. If you go outdoors without protecting your lips with sunscreen, sun damage can cause the same blistering, drying and scaling on your lips as it does on other parts of your body.
Your mouth may tingle for several days before a cold sore flare-up. Cold sores start with small blisters that break and ooze, then crust over. The sores usually clear up within two weeks.
Medline Plus recommends treating dry, chapped lips with petrolatum and beeswax. Avoid hot beverages and foods, spicy or salty foods and citrus, since these can further irritate chapped, blistered lips.
Cold sores usually go away without treatment, but your doctor may recommend using a combination of topical treatments, such as lidocaine, and oral antiviral medications, such as Acyclovir, to decrease pain and shorten the duration of the outbreak. If you experience repeated cold sore outbreaks, your doctor may recommend staying on an oral antiviral to prevent a recurrence.
Drinking plenty of water throughout the winter months can keep your lips soft and hydrated. Always put on lipstick or lip balm before heading outdoors in dry, cold weather. Run a humidifier in your home to keep the air humid. Nutritional deficiencies, such as those of B-complex vitamins and iron, can cause dry, cracked lips, according to dermatologist Nelson Lee Novick, who recommends taking a daily multivitamin supplement.
Cracked, blistered lips are susceptible to infection, according to dermatologist Diana Bihova. In "The Doctors Book of Home Remedies," Bihova recommends applying an over-the-counter antibiotic ointment to prevent infection and a hydrocortisone ointment to speed healing.