I found this on my knee earlier and I've never seen or heard of anything like this before. The thing that made me wonder is the fact that it is a perfectly symmetrical circle of 6 not really bumps, but I guess bumps. Also as you can see in the second pic, I have a scar on my wrist that looks exactly the same. I've had the scar on my wrist for as long as I can remember since being a little kid.