I Was At The Service Station And Loosen My Gas

I was at the service station and loosen my gas cap...a spider with a white sack of eggs fell off my cap to the ground didn't think much of it so I killed it...after pumping gas I noticed my middle finger had swollen a little between my nail and knuckle...not much...no inching ....I looked at it under a magnifying glass and did not see two tiny holes at all...don't know if it was a black widow or not...this happen about an hour ago...should I be worried