It's good to hear of cases where doctors are really taking cheilitis sufferers seriously.
(Although, that probably happens much more than we on this forum realize, because the sufferers who are taken seriously and whose doctors seek hard for a solution are probably NOT the ones who are desperate enough to search for an online forum like this.)
Keep us updated on your allergy tests.
As you know, I ended up discovering that my cheilitis was a reaction to several irritants/lotions that I wasn't putting on my lips, but on other areas of my face and other parts of my body.
I think that most cheilitis sufferers -- the ones who don't have active fungal/bacterial/yeast/viral infections, don't have cancer, don't have hypothyroidism or adrenal insufficiency, and don't obsessively bite and lick their lips -- probably are having an allergic reaction or irritant reaction and need to systematically experiment in their lives to see if they can find the substance that is causing the lip skin to act out.