Best thing to do when you have gotten a phone in water is to first of all power it off. If you can take out the battery. Then I would recommend to take the phone apart so it can easier dry and you can also see if there are visual damages through the water. If everything is dry then put it together. If you are lucky then every thing is working fine.
Otherwise you will have to look carefully on the parts to see if there is corrosion that might be possible to brush away with a scratch brush
[product|IF145-293]
But with water there is always the option that the phone can not be repaired.