I've only had blisters from dirt riding but Casey Stoner reckons P!$$ing on your hands toughens them up.
I do think body position & bar grip is a pertinent thing to think about with braking. When I started practising braking technique I ended up with a lot of weight on the bars which compromised my mobility & control. Dropping your head makes it worse. I had to learn to use my knees in the tank to lessen the weight transfer. Quite alien to begin with.