Your practice regime seems a bit extreme, I would take a break until they heal. However by doing this you have uncovered a big problem, your grip, if you are getting blisters, it means you are having grip problems. The fact that you got blisters by difinition means the club is moving in your hands, a bit like good shoes, properly fitted shoes that won't let the feet move around and you can walk or run all day without blisters on your feet, you'll be tired, but no blisters, by contrast, feet start moving around, blisters show up.

Once your hands heal, work on that grip, try hitting three balls in a round without letting go of club or regripping, you should be able to do that easily, if the club moves after the first or second shot and you must regrip, then your grip is incorrect, either in placement or grip pressure.

As a general rule, usually gripping to tightly will result in blisters, but not always. Sometimes it results from hitting toe or heal shots, causes the club to twist in the hands. Once in great while, it is caused by using the wrong size grip for your hands, but that is rare.

As to practice, I wouldn't go beyond a few buckets, followed by no more then hour on the practice green, and maybe hour on the putting green, you can cover that in three hours easily. would be like playing two rounds of golf. Anything beyond that, and your body will just be too tired, your body will begin to compensate, your swing will suffer.