you made a big loving mistake trying to turn it on when it was wet
This. AFAIK, the reason is that while wet electricity can travel through water to cross wires, which can send nonsense data to corrupt things, induce short circuits and rapid heating, and corrode metal (possibly quicker due to electroplating). If it's left off, the electricity can't forget things over and corrosion is pretty much the only thing you have to worry about.
But yeah, you can try rice but chances are it won't work. I've spilt water on a laptop before and I didn't have the sense to turn it off; I saw each key of the keyboard slowly die one by one until the damn thing BSOD'd.