Like qwazix said, IMMEDIATELY turn off and pull/decouple battery. After that put it upright so that water can flow out, Open all doors, jacks, whatever you may open. Leave it rinsing as long as water flows.

NEVER ever use a hair dryer. Keep it at a non-humid warm place with slight air flow. Or even better put into box with rice or if you have silica gel for at least 24h.

Best would be to disassemble and rinse it with (lay it inside, take care of cam) pure alcohol for a short time and do as above.