Acer Laptop: How to fix/prevent screen flickering/freezing/lines?

Hello everyone! I have an acer swift 3 laptop (SF314-51-5831). It has gotten wet multiple times in the past. Another thing is that I often carried it in my backpack up close to my back with the weight of the backpack contents pressing onto the lid, which caused the hinge screws to come loose. When i recently started using it again after a pause the screen was working fine. But then it started to freeze/become grayscale/ only show top third (see attached photos). I have then taken the laptop apart and took all the tape of the EDP-cable to see if it was damaged. It still looks intact. When I connect the laptop via HDMI to an external monitor the picture is clear. When I hooked the screen back up via EDP-cable and gently bent the screen a while in all directions(just fiddling around) the picture was clear again(see attached photos). What causes this problem and how can i fix it? How can I prevent it from returning when I put the laptop back together? It seems to me there is water damage and I need to clean something but what? I don't want to buy a new screen or EDP-cable only if absolutely necessary. The screen panel is an AU Optronics B140HAN02.1. The EDP-cable is an CA4DB 1422-02GG000. Thank you for your answers in advance!

Kind Regards JB