[Q] Dropped my LG Optimus G in water

Hey, so I got an LG Optimus G off of Ebay the other day and I love it. It only lasted a few days, though. Went to the beach and set it down on the sand to pose for a picture and a wave ran up over it. I had a case on and it didn't seem like too much water got into it. I immediately shut it off.
I know I should have waited longer, but since it didn't look like too much water had gotten into it I tried to turn it on the next morning. I also plugged a charger into it, which I now realize could have been its downfall.

Anyways, it's been a couple days since then and I dunked it in rubbing alcohol to try to remove residue and then took it apart and let it sit under a fan for over 12 hours. I tried turning it on several times and nothing happened. So, after taking it apart more and blowing out the insides with one of those cans of air for removing dust, I put it back together. This time, when I pushed the power button the back button led came on. It goes off after a little while and I can't get it to do anything else. Also, the water damage indicator is still white.

So, I realize it is probably beyond saving, but the back button led coming on gave me hope that there might still be something to do. Any suggestions on anything else to try and any ideas on why the back button led is coming on?

Thanks!

Okay, here's another question. Would I be able to buy another phone off of Ebay that has a broken screen or something for cheap and transfer over the internal parts to my phone? Or is my screen probably messed up too?