What Does Painful Blister Spots On The Palms Indicate?

I have been getting round blister spots for about 6 weeks. It started on my left palm and right middle finger. They are no longer blister, but the areas are still not healed and are mildly painful. About a week ago, one lesion came up on my right forearm. It started with a single blister and is now 6-7 small blisters in a round area the size of a dime.. Yesterday, another came up on my right wrist and today, tow more came up on my right leg. They do not itch. I have found a lot of pictures on the web that look exactly the same, but I can't find out what it is.