What are these weird red bumps on my body?

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I've been waking up ( Or at least noticing in the morning, because that's when I take my shower ) with red bumps. Look at the pictures. Some of them are sometimes infected ( Can't see that in the pictures though... ) like it's a pimple. I read somewhere this happens in winter when there's no humidity in the air to hair follicles - but this never happened before.

Please help. They keep randomly occurring every few days, and they are leaving scars. What could this be?

Also, they don't hurt or itch unless they are infected and have a white bump - then they hurt - usually when I'm walking because my arm slides up against it.

http://img23.imageshack.us/my.php?image=img3283.jpg

http://img23.imageshack.us/my.php?image=img3284g.jpg