I had that once in my thumb and it traveled up my arm in 24 hours, 7 days on anti-B's IV's plus again at home after the insurance company kicked me out of the hospital. Another day later, would have hit my organs. Very serious infection, takes months to recover from it.
Had that in my leg. Got it treated fast and didn't have to be hospitalized, but if I'd been stubborn and tried to tough it out...
Best wishes to Mr. Hastert - there'll be time for politics when he's better.