Possible Water Damage?

I allowed my friend to borrow my enV Touch for a couple days days while I was in an area where I get no service. He gave me my phone back and the screen is acting weird. I am 2 days out of my 30 days. Any way, I think the phone may have been submerged in water during that time, but the phone sticker under the battery is white with red x's, as is the battery sticker which show that it wasn't. Is there any other way to find out if there was water damage to this phone? The screen basically looks good sometimes and sometimes it doesn't, but on the right side, the screen appears darker than the rest of the phone. The speakers work fine. I simply want to make sure if my friend is responsible or if this is a manufacturer's defect because I don't want to hold the wrong person responsible.

i have some water in my screen and was wondering within the 30 days is there a fee to pay for them to exchange it for another?

well water got in because i used the protech invisible shield guard which requires me to use water and i guess the water leaked through and i'm guessing through the speakers

My phone had the touch screen go all psychadelic when it got a little rain water on it while I was walking.  I took it back to Verizon to check it out and they gave me a new one (like 20 days after getting it).  But it was covered under the insurance plan.  I totally agree that it wouldn't be right for them to just give a new phone any time somebody brings in a phone that doesn't work,  that's why you are a fool if you don't get the insurance 

Am I understanding your post correctly in that you actually believe your cell phone service provider should just replace your phone for free any time you happen to break it? Are you against companies making a profit too?

That is like saying your dealer should have to pay for your car insurance.
 
And they sell them for hundreds of dollars because they know people are going to try and scam free phones from them so they are trying to comp. their loses.