I was recommneded Theraputty and also a brill hard ball, which I have to rub across the whole of my underarm bit at a time, very slowly, till it hurts, up and down, then down my palm in the back of my hand. I didn’t believe it but it does work, my physio said that part of the finger problem comes from a bit further up in my case, so pushing with the ball and continuing will release it (not completely) but enough to make a difference.
The other thing I have had to do is try to re-train my left hand to take over a bit, so I have spent a year strengthening that side of things.
My dodgy fingers will not go away but going to the physio eventually after several years of trying to get someone useful, was very helpful. I was very lucky, he was on a six month placement from Portugal and also said he was a general physio, he quietly knew a lot about M.S. or neurological problems. I wondered on the quiet if he had someone in his family who had a similar problem, because each week he came out with more revelations and excercises and proper explanations, not just the fob off ones you usually get.
My right side finger and hand problem is due to higher up damage so my theraputty and ball is a fixer in the short term. When I am watching tv I flex my hands, arms and fingers and sometimes toes a lot of the time. My friend said to do the alphabet with toes. This helps a great deal even though it is a small thing to do. Good luck.
ps on bad days, for me, best to not do anything with the right side hand, I rely on over meal that day. No chopping or anything like that, it only irritates. Then the next day, it will be fine.