Water damage is a bear! So many things can be damaged. Letting a system just dry on it's own often makes things worse. This is more true with systems with a battery.
Always dry it out as quickly as possible. Depending on what hit it you may need to deactivate the acid's or alkali's in the water from damaging things. After disconnecting the battery I would use distilled water as well as isopropyl alcohol to wash down the parts using care not to add any damage from my own actions.
At this point its a hit or mis type of problem. I would start with the logic board.