How Can Chapped Lips Be Treated?

My bottom lip has been peeling every two or three days since 2014. When I remove the dried skin, the new skin dries and peels off again after a few days. It is important to point out that ONLY the parts of the lips which are closer to the opening of the mouth are peeling. The outer parts of the lips which are closer to the chin and the nose are intact and not affected.

History of this problem
Ten years ago, I used to feel worried all the time because of some problems in my life. For this, I used to bite my bottom lip unconsciously, especially while studying for the exams. After four years of biting and peeling the lower lip, the lip starts to dry. I had to apply some Vaseline and lip moisturizer for five years but in vain. The lip remains dried and peeling. If I masturbate, the lip cracks. I used multivitamins and treczimus ointment for 4 months but the lip continues to dry and peel. After using trezimus ointment, the upper lip was affected and it also starts to dry and peel.