Permanent peeling/dry spot on lip

I've had this dry, peeling spot on my lower lip since about 14 (I'm 23 now). It looks slightly darker than the rest of the lip (more purple) and is usually covered with dry skin that peels off completely about once a day. There is zero pain or inflammation. What's interesting is that this spot also goes into the inside of my lip a little bit, and it also peels on the inside.

To add on to this, my entire bottom lip collects this layer of slimy (or dry) dead skin throughout the day. It's worst when I wake up, and these also show up later in the day in smaller amounts.

My dermatologist does not agree that it is exfoliative cheilitis (or any other serious lip disease) and refuses to provide any treatment for that. She has prescribed me different creams over the years (latest being a corticosteroid cream) but they seem to have zero effect. I've also tried other creams and balm, and completely leaving it alone (meaning I won't peel it myself or bother it in any way).

It doesn't really make sense that I would get exfoliative cheilitis in my teens, but its the only thing that fits when I look at the symptoms...plus I acquired it after a summer vacation where I was outdoors in the sun all day.

I've attached some pictures to try and explain better. These don't look as bad as usual because I took them after a shower. Usually the spot is a lot drier. If anyone here can tell me what this might be, or what I can do about it, I would be very thankful.






In the above photo you can also see that purplish area on my bottom lip, that is the part of this dry/peeling spot that goes inside of my lip.