Last year I noticed while I sat out in the sun i started getting little white bumps all over my skin. The more I would sweat the bigger the white bumps would get...they sort of looked like little blisters. They aren't painful, itchy, and they don't bother me. If I rubbed over them the fluid would escape. I have noticed once again since the weather is getting hot i'm starting to get the little white bumps again. What could this be? I'm a female, age 30, 5'6", 140 lbs, and I do NOT have a thyroid.