White screen when phone turned on after volume button repair

I repair phones for a hobby and to make some extra cash.

I was replacing the silent/ vol button flex in an iphone 4s.

The flex is working (based off of vibrations).

However once i turned the phone on after repair I was met with a white screen. The screens still usable, and everything else seems fine.

Did I screw the LCD somehow? Not sure how..

I've tried reconnecting the display ribbon cables, pushing them firmly and even brushing them with an anti static brush.

Do I've to suck it up and buy a replacement screen?

Thanks.