dude where is that at? i have little bumps on upper arm and sometimes it can get acne on your arm..... i know its nasty, but i learned the hardway that human bodies arent all beautiful perfect things, like everybody is saying, i would go get it checked out, and i would put some cream on it for tonight, like some neosporin (just for the hell of it) and if it starts hurting, or if u start feeling sharp stabbing pains out of it, i would go the e.r. right away and tell them u think u got bit by a spider (even if that isnt the case just so u can get in fast, and dont have to wait for hours)