I also get these blisters. They usually itch, I get them on my toes sometimes as well as my fingers. I got a shot of cortisone years ago and had no symptoms for about 5 years. Now they are back. Not on my toes but on my palms and fingers. I never had the palm thing before so it is nice to see that I am not the only one. Try asking for a cortisone shot. The last one I got was in my butt, and 5 motnhs later ther is still what looks like a bruise but it worked for the 5 months or so.
It sounds like dyshidrotic eczema. This is a mild and nonallergic condition that prodcues little bubbles on the fingers and palms. The cause is unknown. If it isn't bothersome, you don't have to treat it, but if it is troubling you, your doctor can prescribe a cortisone-containing cream to heal the blisters faster when they come. Prevention, however, is not possible so far as I know.
Best.
Dr. Rockoff