prince doesn't have bigger butt caps. you just bought a racket with a different size grip. You should put an overgrip on your racket. I coach tennis and my new girls are hurting their hands in weird places but they said it doesn't hurt as bad with the soft overgrip. Also you are probably using your wrist too much instead of a nice long swing with a good follow through. watch pros or youtube to see how a proper tennis stroke is then try to make yours a little better. you may have to record yourself. another thing is that the prince 03 hybrid shark isn't the best for people who want to swing really hard. that racket is made for people who can't swing fast. you should buy a more control oriented racket if you are serious about playing tennis. It will help you a lot in the long run. anyways i wish you luck. let your hand rest if it hurts too bad. who knows... maybe you have tendinitis in the hand. hopefully not.