C.S., I think what your derm said sounds like a great plan to reduce inflammation and prevent negative side effects at the same time. I would give it a chance, for 2 months maybe, before resorting to a biopsy. That might leave a scar.
Healing, I am not in the US and our healthcare system is different so I do not know if Advantan is over-the-counter in other parts of the world. Its active ingredient is methylprednisolone aceponate though, if you wish to look it up. I'm sensitive to so many ingredients that even Bepanthen caused pimple-like clogged pores on my lips so I can relate to the challenge of finding a good treatment. Also, you may try using the steroid only once or twice a week, it may be enough to keep your lips from building up.
And Bradbutter, I don't think anyone who's lying would bother to write this much :) It's not like I'm selling or promoting a product either.