Hello everyone. Strawberry, I once read where some people have dry lips no matter how much liquid they intake, dry mouth, dry eyes, etc. In my case, I believe this is true.
My lips are always, eternally dry. I've forever putting on lanolin or carmex....I have tubes of no matter where I may be. Oddly enough, lipstick doesn't make it worse, but I think that's because of the type I use. Matte, for example, would dry them out even more. Please understand that I don't go many places where I wear it, anyway.
Certainly licking our lips makes it worse, so I'm careful about that. I can't think of a product that I haven't tried...not one. I do drink hot liquids (tea) and that may make things worse and yes, some funguses, etc., may also make it worse. I do get cracks in the corner of my lips, if it's particularly cold.
Wishing you luck in finding out exactly what's causing it. It's possible that something you take regularly may make it worse. Just another puzzle! Yours, Leona