nkubi87 - for a period of time when i was drumming i always had blisters, until now my hands like gorilla, have very thick skin. lol
i think the cause of blisters is when you drum, you exert too much force because you want to play louder, usually during the whole course you dont feel it until when you take a break and then it starts to hurt.
one way that helped me was that i asked my guitarist not to be so HIONG, dont play the guitar so loudly.
then slowly you will learn how to control the grip and then start to play with blister free hands!
alternatively you can get drum gloves or stick plaster on the contact points.