I work for Motorola US, may be i can help u. Usually, the best thing u can do is only in that moment. But...
In the moment: try to open de phone and shake it to pull out all the water. Then use a hair machine to dry the phone as fast as u can.
Later: may be the phone works but the gradual internal corrotion is what damages the circuits with time. Your options NOW are:
*Try another batt in the phone (may be only the batt mess up) Try another one in a cell store.
*If problems persist try to find a repair place who accepts to clean the internal corrotion. Some of them they do it but they dont give u any warr cose in a few month the corrotion comes back.
Wish u luck with that.
۩ ДηтΔгєŞ Яέφụιз₪ ۩
Motorola US Cust. Serv.
Buenos Aires - Argentina