Hi, tired, and welcome! I know moist heat helps but most like hot tubs. I haven't tried a sauna and that is an odd "prescription" for fibro.
Check out the Fibro 101 thread...the second thread on the forum. There are links to good info about fibromyalgia that may help you. Read back posts, too. There is a world of info in them.
I'm glad you joined us and hope to hear more from you soon.
Sherrine