You need to drink plenty of water and also keep your lips well moisturized. Apply a medicated lip balm with a sunscreen to avoid damage due to the sun.
Eat a healthy diet and replace it with any deficient vitamins and minerals.
If your lesions still persist, it would be best to review with your skin specialist for a confirmed diagnosis and to rule out any other cause of the spot.
Let us know if you have any other doubts and also about what the specialist advises.