Got a pus filled blister which broke open & bled a lot . the skin around it is very red and tinged purple and hard lump underneath. spider bite?

Skin infections: Pus filled bumps on the skin are usually the symptom of a skin infection. When they become red, warm to touch and painful it is called cellulitis. Treatment of this includes oral antibiotics and occassionally drainage. See your doctor, because resistant infections are becoming more common and require special treatment.

That or infection...: What you have can either be a worsening infection, or else continued action from a toxin from a spider bite- regardless, you need to get it evaluated as soon as possible, otherwise, without additional therapy such as debridement of dead tissue and/or antibiotic therapy, serious complications can occur such as a blood infection or loss of function of the affect part of the body.