This will have to wait a while, but you might consider asking about an epidural block. My mom had one when she was in her seventies and has had no more sciatica pain since.
Try reading John Sarno’s book, Healing Back Pain
On the hot bath issue, it’s fine as long as the water isn’t hot enough to raise your core body temperature. You don’t want that to go over 102F. This article from the American Pregnancy Association has the full scoop on the issue. Good luck with the sciatica - I had it both times I was pregnant, and although warm baths and yoga stretches helped a little, getting those little squirmers out and off the sciatic nerve was the only permanent cure for me!