If the pain is on the back of your hand, put some ice on it while taking a 30min break. Then wrap tape around the back of your hand and your palm, and try again. It's caused by the tendon being in a state of tension all the time, where it raises above the level of the skin normally. The tape will help keep it down.
You already have a towel in the picture, so there shouldn't be any pain at the base of your wrist.
If the pain is in your finger, swap fingers temporarily. I do this quite often, since I also made the change from index to middle. Middle is faster though, index is probably more accurate... I think... Hard to tell.