Default Note 2 weird screen with video + battery drain

Hi. Some time ago I accidentaly poured my phone with mineral water. It has been rather OK except I had to go buy a new sim and S pen. Now it has started flickering (a gray line) when watching videos and battery seems to be emptying quite fast. Does this mean my phone is dying? Obviously my warranty is void due to water damage so I won't be taking it to service center. I disabeled economy mode (found that in a thread here) and one other developer setting I found on the internet, but it is not helping. Any ideas?