Iphone 4 backlight Problems :(

Hi,

I dropped my iPhone 4 in the toilet 3 weeks ago. The iPhone was only in the water for 5-10 seconds but immediately the screen started flickering and before i could turn it off, the screen went black. I wiped the exterior of the iPhone with a towel and put it in a sealed bag off rice, however i got curious and turned on the iPhone after only 12 hours . Everything worked fine for about 1 hour, but then returned to a blank screen, so i put it back in the rice and left it there for about 1 week. Then after that week i took the iPhone out and tried to turn it on, unfortunately to no prevail. But after hitting the iPhone a couple times it suddenly flashed on and worked perfectly.

The iPhone worked for the next 3 weeks however yesterday afternoon I was recording a video at a soccer game and the screen went blank. Fortunately the sun was shining on my phone and revealed that the phone was still on but the backlight was really dark. The phone still responds to the regular buttons (e.g. vibrate) But i can't see the screen unless shining a light at a specific angle.
I have tried to restore, reset, everything but the backlight is still not working. Plus, i want to see if there is anything i can do before taking it to apple and buying a replacement or buying a repair kit.

Any ideas on fixing the backlight are greatly appreciated Thanks