Water damage, touch wont work

Hello!

My girlfriend just got back home after 6month overseas. At the start of her trip her Samsung Galaxy Note 3 got a minor water damage caused by rain - In other words, this is a 6-month-old water damage

Everything is working fine except the touch screen, it works with the S pen but not by using fingers.

Before buying a new one I would like to give it a shot at fixing it myself. I have however never done anything like this before (but I think I would be able to handle it). But I have no idea where to start. So I would greatly appreciate if someone could point me in the right direction. Which part is most likely broken? What should I start troubleshooting etc?

Kind Regards,

EDIT: I just noticed. If I turn the screen on/off, just when it starts for less than 1 second the screen gets a bit blurry/liquefied in the middle - a circle of approx 2cm in diameter (just as if someone were to push the screen a bit too hard in that area). This could also be "default" blur/move on water effect that you have on Note 3s lock screen (I am thinking that the screen maybe already sensor a touch in that area of the screen because of damage, and therefore the touch is not working?)

Edit2: I have now been able to confirm that it is indeed a constant pressure on the screen causing it to not respond to any other touch (confirmed by changing the lock screen touch effect). So this is most likely not a water damage after all? Anyway, how should I move forward?