Small ( < 2mm) "water bumps" , with seemingly no si

I have been getting these bumps on my forearms (at least I think only my forearms, its hard to see them without good lighting) for a while now, if I scratch them they essentially disappear, and I believe are onset by heat or sweating, I ride my bike most places and in the oklahoma summer its easy to get very hot. They do not hurt or itch, they are just unsightly. They are about 1 mm and the number of them ranges from 4 or 5 to 25-35 sometimes.