Okay, so about three weeks ago I noticed tiny, purplish/red dots appearing under my skin on my thighs. They don't hurt or itch, and usually disappear within a day or two. I have also had them once on arm. Then, about a week ago(still have the spots on my thighs) I began getting itchy red spots from the knees clear down to my toes. On my right knee it is a shade of purple/red with pimple like bumps on it. This morning I woke up and they were a silverish white color and I attempted to pop them, and a nasty yellow pus came out. I have not been taking any medication and am not aware that I have any diseases. I am starting to get a little worried.. I haven't saw a doctor because I figured it was a rash that would come and go. Any ideas on what this could be? Thank you.