Whatever damage happened, did so in the first minute. Plan on a new motherboard, and a new keyboard. Rice is pointless.
If you had IMMEDIATELY UNPLUGGED it, and removed the battery, and the CMOS battery. Then taken it completely apart, and put a fan on it, for at least 24 hours....MAYBE it would come out undamaged. With power on for any length of time, the power causes the circuits to corrode quickly, leaving conductive paths that ruin the circuit board.
Sorry, just being realistic.