Rash on Anastrozole/Arimidex

After taking anastrazole for about ten months, and a few weeks after my last dose of Herceptin, I developed a rapidly spreading rash that is still being worked up. Oncologist switched me from anastrazole to letrozole in case it was an allergy rash from anastrazole --- but the first two biopsies said it's not allergy, or bc mets, but couldn't say what it was. Two days ago I got to see the dermatologist, who also could not make a definite diagnosis, took two more biopsies (I'm getting to look like swiss cheese) and a slew of blood tests. Said it was definitely not allergic, but could be one of several serious conditions, or even a blodd cancer from chemo Put me on high dose steroids by mouth and by ointment that I have to smear all over every night. Since the rash came up just as the Herceptin was washing out of my body, I asked to be put back on Herceptin, but docs said no

My blood pressure, which has always been very low, is now a bit too high --- not sure if it's the letrozole, or whatever is causing the rash (not the steroids, started rising before that). I'd prefer to go back on the anastrazole to see if my blood pressure comes back down, but have to stay on the letrozole until all the test results come in

Anybody else get weird rashes from anastrozole? I saw another thread here about lichen planus from AIs but my path results do rule that out