My girlfriend had one like that in her thumb. In several days it started getting red and I told her to get the hell down to the doc in the box.
She didn't want to go because it was Sunday.
On Monday I bitched at her some more, she went to doc in the box, they sent her right down to Mission Memorial Hospital. She was one day away from having her thumb amputated. Close call.
She just got loaded up on antibiotics.
