There is no simple answer to this question.
If it has just got wet, turn it off and leave it off until it is thoroughly dry. Keeping it in a sealed bag or jar of dessicant for a couple of days is often recommended (silica gel is best, but uncooked cous-cous or rice can be used) - and note, I did mean "days" rather than "hours". Turning it on while there is still moisture in it risks further damage.
But if it is already damaged then it depends on what is damaged what is needed to repair it. It basically comes down to "replace the damaged components and hope that you got them all". In many cases it is not economically viable to repair it (which is why most warranties won't cover liquid damage).