Mark,
Take a look at the photo in Post #6, here:
https://www.mobileread.com/forums/sho...=kindle+screen
If that's what your screen looks like, then you have a fractured substrate. As you'll see from that thread, your only recourse is to replace the Kindle. You can try to get a free or reduced-price replacement from Amazon, but there's no guarantee you will succeed.
I was lucky. I hope you are too.
Mike