Patient Went On A 6 Mile (3 Miles One Way)

Patient went on a 6 mile (3 miles one way) above 9000 ft. When he returned, he had me check for anything on his back side as it was sore. It was red. he said it was painful.

A week later, he went to bed feeling ok; then within minutes he became chilled. In he morning, he was sweaty and hot. Took him in to doctor. She thought it might be infection. put him on antibiotics.

She also drew a line on the rash area, and it has grown aand is continuing down his uttocks to leg.

Any ideas?