What Causes Pus Filled Blisters On The Legs?

I have small bumps on my legs. I have done some research and I think it might be Keratosis Pilaris but I'm not sure. Also in my research I discovered that you can't get pimples on your legs but these bumps seem almost identical to blackheads. I popped one( and I know I probably shouldn't have but I wanted to know what they were) and out came some blood and pus, like in a pimple. COuld you tell me what these are and how to treat them?