I had sciatica about a decade ago.
My back was hurting badly and I could hardly move - getting out of bed was a five-minute process involving multiple different positions, where I finally rolled off the edge of the bed and my wife helped me to my feet. Anyway, I'd been to the toilet and was very gingerly straightening up when I felt something "pop" in my spine and I had a sensation like a rush of cold water down my right leg, then it suddenly went quite numb, apart from a pins-and-needles feeling.
My wife had to drive me to the doctor as I was most definitely not able to drive, as I could hardly walk. He immediately diagnosed sciatica, but got me to have a scan to confirm. One of my lower discs had popped out a bit at the side and was pressing against one or more sciatic nerves, which was causing the numbness and pins-and-needles.
He gave me a prescription for a corticosteroid called prednisone and told me to spend a week in bed, flat on my back. I was to take quite a lot of prednisone on the first day and then taper down over the next five or six days. This would reduce the inflammation in my back and would hopefully release the muscular tension and the disc would slide back into place. He also gave me a script for Panadol (acetaminophen) fortified with codeine for back pain.
At first, it was still painful and uncomfortable and it was boring as hell. However, it worked! At the end of the week, my lower back still felt slightly sore, particularly when it passed through one angle as I was bending or straightening up, but the sciatica was entirely gone and although my back still twinges a bit if I twist around too quickly, I've never had sciatica issues again.
I don't know if corticosteriods and not moving for a week will work for you, but it did the trick for me.