They were probably water blisters.

When I was sixteen I went to a theme park in late May with a bunch of kids from school and I forgot sunblock. The chaperones were really concerned because of my skin tone, but we couldn't stop for sunscreen. So I go out and play and have fun in the blazing hot Atlanta sun and it's amazing. For hours and hours.

Then we go to the water area of the park and I get sopping wet. And mysteriously turn bright red. Mysteriously.

So we go home, I nap on the bus and get kind of itchy but I'm okay.

I go to sleep that night and at about 5 a.m. I wake up in smurfing agony. Never been in so much pain. I stumble to the bathroom, turn on the light and after like five minute manage to peel off my shirt (and quite a bit of skin) and I have a solid, continuous water blister spanning my entire chest (I was wearing a square neck tank top.) I was out of school for two days.

Never again!