This is a common problem, had the exact issue with my nexus 5. What I found worked was tapping the home button against the table and over time whatever was causing it to stick went away and hasn't had issues with the power button ever since.
First things first, BACKUP YOUR DATA. Don't want to chance losing everything. At this point it's a 50/50 shot if the water damage has caused permanent damage or not. If everything is working now you may have dodged a MAJOR bullet, but better backup just to be safe.
Try checking the screen settings on your television. On my LG I can set different lighting settings for different inputs, and some cause the screen to appear darker than others. Each input on your television will have different pictureh modes so setting it on one input will not automatically transfer it over to another.
You can check local repair shops in your area to see if anyone does house calls, but most of the time, depending of the model and age of the printer, it is much cheaper just to buy a new one than it is to replace the printhead.