Angular cheilitis is a common condition that causes painful cuts, cracks, redness, or irritation at the corners of the mouth. It can happen due to dryness, repeated licking of the lips, fungal or bacterial infection, nutritional deficiencies such as low vitamin B or iron levels, irritation from cosmetics, or prolonged moisture around the mouth. Since you regularly use lipstick, it is possible that certain lip products may be irritating the skin or worsening dryness, especially if the lipstick is old, expired, or used frequently without moisturising the lips. To help healing, keep the corners of the mouth clean and dry and apply a plain lip moisturiser or petroleum jelly regularly to protect the skin from cracking further. Avoid licking the lips, peeling the dry skin, or using irritating cosmetic products until the area heals. If possible, temporarily stop using lipstick for a few days and switch later to a gentle, good-quality, non-irritating product. Eating a healthy diet rich in iron and B vitamins, including green vegetables, eggs, fruits, milk, and nuts, may also help if nutritional deficiency is contributing to the problem. If the cracks are persistent, painful, associated with white coating, swelling, or not improving within 1-2 weeks, you should consult a doctor or dermatologist. They may prescribe antifungal or antibacterial cream and sometimes recommend blood tests to check for vitamin or iron deficiency. With proper care and treatment, angular cheilitis usually improves well.