Had a similar issue 20-15 years ago. After seeing many professionals and trying all kinds of treatments (I did it all - biopsy, injections, Rx topicals, diets, total isolation, etc.) ,I was eventually prescribed Lamprene (this was after seeking out the best expert on this topic who was at John's Hopkins. Dr. James Sciubba. I drove to Baltimore from NYC to see him for several appointments). I was on this oral treatment for multiple years and it got my issue under control before I stopped taking it. I would've probably continued taking it, however my new PCP suggested I stop to see if I still needed it. After I stopped taking Lamprene, my condition was under control. Still I have dry lips and carry vaseline with me, but far far far improved to the point I don't think about it at all.