Last night i noticed a red pimple-esq dot on my left shin. I originally thought it was a spider bite or that i had whacked my shin. This morning a woke up and the area around the red dot had swollen and was giving me some pain. I've gathered that it's not a pimple and i don't remember whacking my shin in the past 4 days. Last time something like this happened it was on my forearm and it was a staff infection caused by a spider bite. Could this be similar. I'm not terribly worried, but this seems out of the ordinary.
[Pictures of the dot. Not the best, but it's something. The swelling isn't very apparent but it's becoming a noticeable lump](http://imgur.com/a/xRlis)