After the fact?
Pull the battery and try to get access to a Vacuum Pump.....
this is the single most effective method.
open the phone as much as possible, remove anything that you can, SIM card, etc....
place the device in a container than can be sealed. bottle, can, etc....
insert a nipple into the lid of the container, connect a hose to the vacuum pump.
pump until the gauge reads 26 inches of Helium and hold that Negative Pressure on the container for a minimum of 3 hours.
that is just about guaranteed to remove all of the moisture.
The Rice in a bag trick works well, but you must be patient and allow it to sit in that bag for 48 hours to be guaranteed all the moisture has been absorbed from the phone.
IF, the battery was left in it, and the device turned on again...
all bets are off.... most likely fried something inside.