Somany color lines on my display

@narimacna this sounds like either a bad LCD flex or a bad LCD. You can take it apart and check your flex cable and the connector for tears, debris or corrosion. Ultimately so, it sounds like you will need a new display.

Use something like this video to repair your assembly. While you work on your phone, take lots of pictures. Once you are done with it, take those pictures and create a guide for iFixit. That will help the next person that has the same problem as you do. It's easy and fun to create these guides. https://ifixit.com/Guide/new The iFixit community will appreciate this.