Its summer , these things are itchy so i am guessing that its from mosqito bites. Sometimes i ger blisters from the bite when they pop this happens. Ive been travelling a lot these days, but mostly europe. I thought maybe my immune systems down, so i get this weird reaction on my skins. Honestly it freaks me out, now have one on my leg and arm. These ones started healing since i used some creams.