I think i have been bitten by a spider. my hand is swollen and red. it has been 3 days not the reddest has gathered to one spot. the spot is really red and has blisters. i have taken antibotics and benyagral. no doctor

Hard : Hard to tell what type of spider and whether this is infected without a picture. Any chance it was a brown recluse spider (those bites typically get worse and the skin can break down into a sore/ulcer)? Since it sounds like this is not getting better and is red and swollen, i would recommend you see a doctor for evaluation and treatment. I hope that helps.

Go : Go see someone, there are several different types of bites, most commonly a brown recluse spider that needs additional treatment. You may have necrotic ( dead) skin and tissue just below the surface that can be infected easily leading to more issues. While many bites do not lead to this amount of severe problems, the bite that get worse a few days ater is something to be concerned about. Special topical medications, surgery and prolonged treatment for a wider bigger area of skin and tissue necrosis ( translate skin and soft tissue death) can result if this progresses. That being said, not all spider bites are brown recluse bites but if it is not getting better, its better to be evaluated.