What Causes Blisters On Chest 1 Week After Periods?

I am 37, very healthy and normal weight and have noticed that the week after my period I break out in blisters across my chest. this time none there but a patch on my neck under my ear and one random one on my leg. they are oozy and itchy and i hate them. i'm guessing its from aging/hormones. am i the only one with these symptoms? if not, is there something i can do with my diet to offset the symptoms without going on any medications? thank you