You do have an abundance of overlapping issues, quite a puzzle. 1. Not sure why the doc wants a second biopsy. My biopsy came back negative for GD, but the symptoms were abating. Still 100% certain I have it, as I am a classic case, even doctor agreed another biopsy with active breakout is unnecessary and we both figured it served no purpose. 2. MGUS, that's a new one for me but looked it up. It is interesting that some patients that develop MGUS later develop lymphoma. That is a tie in to GD, as lymphoma and leukemia are common indicators GD. 3. I can't wright strongly enough that you get the 5 Day Extended Patch Test. Do that first before you get a second GD biopsy. Is your doctor licensed to perform this test. I went to derms that were not licensed to perform this test and they never recommended it!!!! Still angry. I had to learn about this test on my own, like you and others desperately seeking answers for problems no doctor was able to help me with. Allergies could be the cause of skin sensitivities, this test literally saved my life. What have you got to loose? It is not comfortable for 5 days, but not painful except where you might have a severe reaction to a chemical of element activated on patch. For me multiple sites were at a plus 3 (highest reaction) and those were exceeding itchy, yet I gladly toughed it out desperate to get a name for my tormentors. It is absolutely impossible to guess what these may be as many chemical and even natural elements are added here and there into our daily contacts. However I don't believe it would be possible if you had a back torso rash GD breakout. 4. Fatigue- I felt fatigued from lack of sleep based on painful or itchy symptoms. Yet right now am symptoms free for all my forms of eczema and have not noticed any fatigue, but I get a good nights sleep. I will be turning 70 soon and must admit my normally hyper nature has slowed especially in the last few years. Getting projects finished takes longer and I need to get off my feet by 8 pm once dinner dishes are done, because my legs start aching, but I realistically think that is a part of getting old. I am not sure of your age.