Help LG Optimus L90 Screen issue

My phone has become non-responsive to touch. I believe the fault is a small crack above the face buttons, but it's been there for months and I'm only starting to have issues.

It is a rooted phone. Could software be the cause?

If I factory reset the phone, would this remove the root so I could get a replacement unit that functioned correctly? (I need to know this, I'd like to keep the phone. )
- If I do have to factory reset, is there any way to backup my photos/files without my screen?

I have tried several methods to fix it. No dice.

Are there any methods to fix it?

Any help is appreciated. Thanks in advance.

EDIT: I've also had a problem where the phone would press down in a different place then where I touched the screen, forcing me to reboot it.