Itchy liquid filled blisters Since I'm back from Minnesota

So I got back from Minnesota almost a month ago and ever since I've been back I've been getting tiny blisters filled with liquid that only itch right before I pop them. And usually how I pop them is I just scratch it. I've only gotten 3 so far, one on the top of my foot, one near my knee, and one on my shin. I'm wondering if I have a disease or infection and if it will spread amymore. And how to treat it. Thanks guys.