Has this data not been synched with your computer/itunes ever? If it has been, you can use one of many data recovery programs available like wondershare etc.. which use the backup file generated by itunes. If that isn't the case you might be **** out of luck.
Did you try connecting up to itunes and seeing if you can restore by some miracle? Can you get into DFU mode? The chance of this working is slim to none though, sorry ;/.
I think there's a good chance your battery is *#%%'d up.

But I HIGHLY doubt it stops there
If it was powered down (battery out) when it was dropped into water you would be in a whole different boat.
What type of water was it dropped in? Tap, salt, ?? You could try removing the battery and dunking/washing/saturating your phone with distilled water then drying it out using silica or a legit desiccant. Rice does work but simply does not compare to a home-made silica chamber. The purpose of this would be to remove what was IN the water i.e. salt, dirt, etc.., which may have very high electrical conductivity.
Chances are it won't make a difference.. if your unplugged x-box was flood damaged with seawater, using distilled to clean the salt/dirt then fully evaporating it would likely have it working good as new. However, electronics that are powered up when they make water contact don't have much of a shot in hell.