My lips are so dry and i can't even stay in an air-conditioned room for long. what vitamins am i lacking? if needed, i will take the medicine.

Dry lips: First, make sure u drink plenty of fluids and keep ur lips well hydrated/ moisturized at all times. Try applying petroleum jelly over ur lips before u shower and right after u come out of the shower, without rubbing ur lips off with a towel first. Thsi seal sin the mositure. Do not lick ur lips to moisturize thema as the saliva breaks down the protein in your lips surface.

May be food allergy: Riboflavin (b2), zinc, or iron deficiency can cause cheilosis (cracked corners of mouth), so it may help to supplement with these. Check with your doc. In addition, you could have a chronic food allergy causing your cracked lips. Common causes include gluten/gliadin (wheat), dairy, soy, and eggs. An elimination diet may help. In the meantime, keep lips moisturized with non-petroleum products.