Hello,
Well, what a surprise! 
I am glad you finally found the problem.
Anyway, if the pin is really “fried”, there is nothing you can do about it except to switch to another pin or buy a new board. It could have been caused by a short to power or ground, so one strategy to avoid this in the future is to protect all output pins with a current-limiting resistor (e.g. 220 ohms).
-Paul