Touch screen not responise in some areas

Hello,

My Nook Hd Color 7 inch developed a strange fault. Screen became "dead" in few areas- mainly sides., especially right side.

I have tested it using an app and you can see results here. First photo shows horizontal slides, and second one shows vertical. You can see the gaps,

I have cleaned the screen on the edges and done faxtory reset- didnt help. What can be the problem? Is it worth opening it up ? If yes, what should I look for? Thanks

https://snag.gy/Zo2B0y.jpg

https://snag.gy/mC0aek.jpg