I got bit by a spider and it hurts and is red and hard should i be worried?

Likely an abscess: Unless you saw the spider bite you, it is more likely to be a skin infection instead (most likely mrsa, which is an aggressive bacteria). It needs to be evaluated by your doctor in order to drain it and or give you antibiotics. If you have fever go to er. Put warm towels on it at least four times a day. Don't try to squeeze it but if it has a "pimple" you can try to open it with a sterile needle.