Sounds like you have found a great doctor. Perhaps you should follow her recommendations for testing if for nothing else to rule things out and give you the peace of mind that you are doing what you can to get better. Pleae let us know what you learn from the tests and how you decide to proceed.
I don't think carefully trimming off the edges is too harmful (if at all). I do it, but am having to do so less and less as the crusts get smaller and smaller and come off easier and easier on their own. You'll get to this point, too. I am sure of this considering my belief that our cases of this condition was caused by the same thing - chapstick.