Yup - we've got pain and problems, but these suggestions help.
My biggest pain is in my thumb joint. I have moved to a Sizzix Die Cutter and am using my rotary cutter less.
When I do need to rotary cut, a sharp blade is essential. I have tried every brand (I think), and the Martelli is the easiest on the thumb for me.
I also switch hand projects - from needle work (quilting, embroidery, applique) to knitting - every couple of hours or so.
I use ice-heat-ice (15 minutes in immediate rotation) as often as I can make myself do it. It seems to "trick" my metabolism. Learned this trick when I had a cervical fusion and a plate inserted to keep me upright...