Speaking as an IT tech for a well-known Uni, who has problems with my hands...
I strongly recommend Microsoft or Logitech OPTICAL full-sized mice (& keyboards). They have some of the best ergonomics, and your paws won't hurt so much.
MS also do a small (kids size) mouse which is an option for some!
Avoid those mini & micro mice, they will turn your hands into claws. Remember if it hurts, stop doing it, & take medical advice.