Screen Blackout problem after water damage

There really is no use fixing a device that is water damage as everything can be damaged and its hard to find out what is and isn't. And it also seems like the backlight might have died, you could try replacing the screen but I wouldn't recommend.

mhk665, "water damage therapy by keeping it in air tight rice for one week. " that is more like wishful thinking than therapy. Rice is great for cooking, but it has no place in electronic repair. Using rice is about the same as doing nothing. It will not repair your phone nor will it prevent any kind of corrosion. The best thing to do is to stop using the device, (remove the battery) and to totally disassemble it. Here are the guides to help you with that. Use some sterile water and rinse the parts off to remove the sale. Then clean it with +90% isopropyl alcohol and a soft brush.. This will displace the water and stop corrosion. Use this guide to get it cleaned. It is written for a 3G but applies to your phone as well. It is okay to submerge a board in isopropyl alcohol. After that, air dry all the components. Do not forget to clean the connectors on the board as well as the cables. Then re-assemble with a new battery This is not optional but a must to avoid failure later on. Check your board for any missing or damaged component. Re-evaluate after you clean the phone. If your backlight should still not work, test the 6R8 coil. Use this video or this one and see if it is time to change that coil. Now, if a coil replacement does not resolve your issue, there is still the possibility that it is your backlight IC 109B that is giving you the trouble. That will be harder to replace and will require special tools and techniques. Of course, you would also want to try a new display assembly. Water damage is the toughest to trouble shoot and to repair. Hope this helps, good luck.

can you get i fix? how much will it cost?