First, lack of nutrients could be causing the poor hair growth. That said, I reco a thorough thyroid work up including antibodies. You are autoimmune and thyroid is an obvious thing to watch.
Second, as squirmy said, you may not flare like this for two years. I have flared but they are a FRACTION of what they were - quite livable. As the antibodies fall the rash lessens. My last outbreak was no more than a minor irritation, and the intensity fell drastically in the first few months after going gluten-free and li.
Third, I'm allergic to sulfa and never tried dapsone.
Fourth, ice packs and pressure at night to help you sleep. Coat your body in ice packs.