James, it serves no purpose to practice so much that you get blisters that prevent you from practicing. Find the point where blisters begin to occur. Practice only until that point and no more. For me, that point is about 500 balls. When you must practice longer than that, go to the practice green or chipping green and continue your practice there. It will be very difficult to get blisters when you putt or chip.

You appear dedicated, here's some reading material for more information on practice:

http://www.golf-tuition-online.com/ge...se-method.html