Blisters From Sun?

Hi- here is something odd that started happening to me last summer, and is happening again this summer. Every time I am out in the sun I get these little blisters on the tops of my hands and feet. Even if I haven't gotten enough sun to burn or wear sunscreen these blisters appear. The ones on my feet itch! Does anyone else experience this? I have a feeling it's a type of sun poisoning, but like I said, it only happens on the tops of my feet and hands. My skin is a bit fair, but after years of stupidly thinking I could tan (my best friend growing up got really tan and I thought I could hang ) I can get tanner than I should, imo. Any ideas ladies?

Thanks for any input! -lisa