Google Nexus 5 — Problem on the screen or in the Dock board?

All right guys?

Well, let the sad story! kkk

Dropped my Nexus 5 in water, then immediately turn off.
Quickly I opened my device and let the components dry under a fan for two days straight. When reassembled all was working perfectly without any problems and continued for two days, when out of nowhere the screen started flashing and change the brightness level until maintained a very low level, and the brightness control does not work anymore.

Realizing that something strange had turned off again as quickly as possible and let him open under the drying fan, now for 3 days. This time after drying the cell returned with the same brightness oscilation and in no time the screen went out and now rarely blinks showing the system running smoothly in the background. I receive notifications and everything but the screen does not turn on.

NOW THE DOUBT!

By opening and reopening the phone I realized that the screen connector (marked by the red rectangle) was slightly dark in the center, even cleaning with a small rubber school oscillations continued until the screen doesn't work.

Since I have no availability to get parts to precise tests, i need to risk buying a new screen for $ 300 or only the bottom dock plate (marked in yellow) for $ 70 to exchange even at home. But I'm not sure what was making trouble, I'm thinking it may even be neither, I think it unlikely because everything else works perfectly but... you never know. = (

Looking the symptoms of what happened, kkkk there is someone who has more right guess what I should change exactly?

Thanks so much and sorry for my bad English. =(