Looks good with me and I see no problem with your kissable lips, though you are experiencing irritated about it. As you suspect due to your biting habit that cause for your lips to feel. My daughter (3 years old ) Had a habit to peeling the skin on her lips and she never bite it like the way you do. So any update with your Derma prescriptions?
I had also that exp. before but not more often, it's because I eat a lot if acidic fruit or too much dipping with vinegar, I remember also when I was a kid I am putting rock salt on my lips after I eat a lot of unripe mango and then I peel off the skin.