I would try cleaning underneath your key caps and see if you can get your keyboard to function afterwords. The best way to do this is to remove the key caps from the keyboard itself. There is a guide on how to do this that I will link [guide|117547|here|new_window=true].
I would also check to see if the ribbon cable that connects the keyboard to the logic board is seated correctly and is not damaged (I.e. any creases in the cable). If none of that works, it could be that the switches for the keys are damaged in some way, which means you would need to replace the keyboard.
Definitely try to clean the board first, and make sure that the cable is good first before looking for the replacement.