My chelitis started at the age of 17 (9 years ago) after I bite by accident my upper lip in the center. It was painful but it didn't bleed.
The damaged area was first only the center of the upper lip, but the cheilitis spread to the border in few weeks. Indeed, the white stuff (you can see a picture in this repertory) that I can see especially the morning when I wake up (because the mouth is closed and I don't "swallow" during my sleep, sorry for the poor english) becomes a crust when it comes in contact with air. When the crust goes away, it can spread the damaged area.
After 5 years, the cheilitis touches the bottom lip. Maybe, I was trying an inappropriate creme, I don't remember exactly the cause.
WHAT I HAVE LEARNED
Today, every time I weak up, I immediately brush my teeth and the whole mouth. So, I remove the white stuff with my finger and water when it's still liquid . I do that at least 3 times per day. If I don't remove this white stuff, the crust grows faster but it didn't resolve the problem at all, it just slow down the condition.
But the crust is still there after 5 days, and it's always very painful when the crust keep your lips static or when it goes away after 10-15 days: it's a burning feeling.
I don't think that this condition is necessarily related with psychologic problem or anxiety (what says physicians). During 9 years, the condition didn't improve and I was not always in bad mood of course.
I try antidepressant (Zoloft during 3 months) : NO IMPROVEMENT
In my case, I don't smoke, I don't drink and I think that I have a healthy lifestyle (about food, sports...)
My dentist is trying to remove Amalgam filings : The job is 80% done but there is no improvement at this time. I will update if it does change in the future.