Hello,
Firstly,It can be due to vit B deficiency.Take some vitamin B complex for some days and see if your symptoms improve.
Secondly,it can be due to atopic
" refers to a group of diseases where there is often an inherited tendency to develop other allergic conditions, such as asthma and hay fever). Cheilitis(Inflammation of the skin on and around the lips)is often seen in atopic dermatitis. Avoid licking the lips as saliva evaporates quickly resulting in them being drier than before. Drink plenty of water and take multivitamin supplements and do not apply lipstick or other cosmetic products for some days. Use a humidifier to moisturize the air in your home and apply shea butter or Vaseline on your lips.You can also use a homemade ointment mixed from 1 tsp glycerine, 1 tsp lemon juice and 1 tsp castor oil. Spread on lips overnight, refrigerating the leftovers for future use. Eat foods high in calcium, magnesium and flaxseed oil. If a week of compresses and emollients don't do the trick, you can add over-the-counter 1 percent hydrocortisone ointment to your regimen.
If the condition still persists or there is deep cracking in the region of your mouth,then please consult your doctor as it can be due to infection(Angular Cheilitis).Antibiotics are needed in such cases. It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.