Carving will change your hands. Your off-hand, or "support hand" as some like to call it, may collect litte cuts and scars. While your dominant hand, the one you use to hold the knife, axe, or other tool, will proudly develop calluses as a result of the friction of so many hours spent shaping wood. Both hands will grow stronger as you develop muscles you never knew you had.
For cuts, I keep a first aid kit close by. Working with knives has made me an expert at treating minor cuts. It happens less often than it used to, but I still make the occasional mistake which requires a band-aid or a spot of super glue.
For sore muscles, I do two things: hold a hot mug of coffee or tea, and take breaks for stretching. Like a runner stretches his or her leg muscles, a carver must stretch those muscles in the fingers and hand. This should be as routine as stropping your knife blades. At the end of the day, an application of Mineral Ice can help as well.
Steve Tomlin has some great advice on hand stretching and excercise. While you're over there, check out his amazing work in green woodcarving!