There have been several posts like this recently, If it's only 1 fish, odds are that is nothing to worry about (except the loss of a really nice fish), it's common for bass to develop problems, (i.e. sores and small fungus like growths) related to post spawn stress. I would keep an eye out for other fish, but it's probably just nature taking it's course. (just fyi...I still have a handful of bass on their beds, so spawning related problems may occur over the next month as well.)