Copied from various sources found with google search How to prevent chapped lips
Ensure your body is not deficient in B vitamins, iron or essential fatty acids. Consult your doctor.
Hydrate your body by drinking plenty of water.
Keep the air moist in your home. Dry air is a common cause of chapped lips. Use a humidifier in your home, especially at night, to help keep the lips moist.
Avoid exposure to wind, sun, or cold, dry air, breathing with an open mouth, licking your lips, and contact with irritants or allergens in cosmetics or skin-care products.
Protect your lips. Use an oil-based lubricating cream or lip balm containing petrolatum or beeswax.