It usually takes a pretty good scratch to damage a circuit board. The outside layer of the board is a protective insulator. The copper needs to be completely severed before conduction is lost. As long as the copper is not completely severed, or peeled off so adjacent traces touch, I would try the board and see what happens.
Incidentally, when the magic smoke leaves the chip, then it really is game over. Haven't seen any exceptions, unless the chip never did anything in the first place.