I am having similar problem with right thumb. It has limited my sewing time, but, what has helped is icing the inflamed area. When I sit to watch TV I get a gel pack out of the freezer, wrap it in a kitchen towel and put it on my thumb. Eventually, the swelling went down. It did take a while, couple of months. I found pain pills made my blood pressure go up, so had to find alternative. Chiropractor also did adjustment on thumb and suggested ice. Hope this helps, as I know how frustrating it is to limit your sewing time.