A water blister has no pain involved at all besides some discomfort. They are clear in color and involve trapped interstitial fluid surrounded by thin onion-like skin. The skin is thin because it is only one layer. They should feel like tiny balloons full of water. They are caused by a weakening of the tissue that is not unlike getting a hemmoroid. Since the tissue is weak... the chances of getting more recurring water blisters are high.
The pain occurs when the layer of skin finally sloughs off. The pain and discomfort can be REALLY intense after the damaged skin dies off though. You will want to use some sort of bandaid or bandage to protect the raw area after the skin sloughed off.
Are you sure that those are blisters?
Blisters shouldn't take more than a week to slough off...
When you do get a blister, go ahead and sterilize a sewing needle, carefully pop it and squeeze out all of the fluid.
If it is not too bad, you will then need to apply some kind of cold to the skin so that it shrinks back a bit. I use a shotglass filled almost to the rim with frozen water (I keep it in the freezer next to the frozen pizzas). I take the ice filled shotglass and run a thin film of water on the top of it. I then take the shotglass and touch it to the blister or the area that gets blisters for about 15-30 seconds.
You should then apply some kind of ointment like Carmex that will speed up the healing and simultaneously protect the wound. You will need to keep applying the Carmex or ointment of your choice every hour or so... just a little dab on the blister site. I usually wrap my ball sac up and over the head of my cock so that it is protected and then put on a pair of tight white cotton briefs that holds everything in place. Don't make sudden movement when your blister is healing, it will shift everything in your underwear and may wipe off the ointment, resulting in sharp pain and discomfort .
Applying the ice shotglass to the area which gets the blisters when you don't have a blister is an effective technique for avoiding blisters as well. It is more effective as a deterrent than as a healing technique.
When you take a break during pumping, apply the ice shotglass to the area for about 20-30 seconds and then get back in the tube. When you are all done pumping, apply the shotglass as a final precaution and to shrink that skin that wants to bulge out.
All in all, the area of your penile skin that gets blistered has some errors in it's matrix. You will need to go slow and allow your body to replace the damaged skin structure with properly grown tissue. | 
