How Can painful Blisters On The Arm be Treated?

Watery blisters suddenly erupted on the inner side of my left arm, from the palm, thumb and forefinger to above the elbow. The skin above the elbow to the shoulder is red but so far no blisters have appeared. I have the lupus antibody, with arthritis, clogged carotid on the left side, and heart stents, so don t know where to look for the cuse of the blisters. Have considered shingles, chicken pox, or perhaps peripheral vascular condition but am at a loss. Have been putting aloe vera on blisters.