I think i got bit by a spider last night my leg was painful and there was a red hard lump. today it's still very tender and the redness has grown?

SPIDER BITE: All spiders contain venom... it is how they kill their prey. Most venom is histo-toxic... It inflames & at times destroys tissue. The redness represents the venom 'leeching' out from bite site. Sometimes the redness will become black in the middle & 'follow' the redness. The size of spider bite wounds should be VERY CLOSELY monitored to make sure they are healing properly!