Does this look familiar to anyone?

Sunday afternoon I grabbed a wool hat out of the hat basket by the coat rack and went for a hike. Along the way I started itching and figured it was because I had worked up a sweat. I left the hat on and completed the hike. I think I had a little itching before I went to bed but nothing major.

Now, three days later I see red spots starting to form and they are somewhat swollen a a bit larger making my scalp a little tight. They aren't terribly itchy, I have a head ache and feel a little tired but not too bad.

My first thought was some kind of spider bites. I don't think it's a brown recluse or there would be much more pain. Other than that, anyone seen anything like it?