Iphone 5 Brightness Problem? - 1

So I damaged my iphone 5 using it in the rain a couple months ago. It shut off for 3 days, one of which I brought it to the apple store and they told me that it wasn't under warranty because the moisture strip things were activated which I figured. I put it in rice and after a few days it started working again fine, just with broken cameras.
So I've been dealing with my phone for the past 4 months because I can't afford a new one and recently it's been having brightness issues. The brightness has been really low and sometimes it goes back to normal for a little bit but it's really unpredictable. I was messing around with the brightness today and it just completely spazzed out and now I can only get the screen to flicker. I've tried turning it off and on and plugging it into the wall and the screen flickers and the touchscreen still works (I can shut it off using the touchscreen) and the vibrate works as well.
What I'm asking is, is there any way I can get the screen to work again? Is there something I can do if I plug it into the computer? Also, what kind of issue do you think this is? My dad thinks its a problem with the logic board so we've considered buying a new one and replacing it, would that be a good idea?

This problem is due to ic which control your display leds that ic is distroyed due to water so go to apple service centre and fixit or ask them that what is the problem in the phone