Screen dim in half the screen

What are lines? I have a similar problem and I am trying to determine if a repair is possible. My entire screen is dim. Does this mean that replacing the display will not make a difference?

The lines I am talking about are basically wires printed on the circuit board. They both come from different power controllers. Have you tried checking the accessibility settings and making sure the white level isn't turned down? Also be sure that the zoom function isn't on full screen and set to dim the screen. The backlight isn't completely out is it? A photo may be helpful. I will help as much as I can.

@kaniggit49 is correct about getting your logic Board properly cleaned right away...sooner the better! It requires removing the shields from the logic board and using an ultrasonic cleaner with a solution for electronics to properly decontaminate and clean it (Like Branson EC). Then as @carsandiphones explained, the backlight circuit is most likely damaged and in need of Microsoldering (NOT a DIY job). You can Google Repair shops near you to find a reputable shop that does this kind of repair or search the IFIXIT Pros page to find one that offers mail in service. Replacing the LCD would not repair this issue due to a short somewhere in the backlight circuit. Either a bad IC Chip, Coil, Diode, Filter (Fuse), or capacitor has been damaged and you will need an experienced tech to troubleshoot which component(s) will need replaced.

The problem you now face is, even if that issue is repaired...water damaged phones have hundreds of small components on the Logic board which can have corrosion under them and cause future issues. Most repair shops do not like to do this type of repair because of this and there would be no way of offering a warranty and would offer the service mostly for Data recovery and then you could just use it till you couldn't any longer...a hour, day, week, month....year...no telling. Just do not attempt to charge it, power it on and even disconnect the battery if you can. Water on the motherboard should be cleaned as soon as possible to prevent the growth of corrosion and causing further damage.