Rooted & Xposed: Was fine for days, then screen corrupted. Now, screen won't turn on.

I have an H812 in Canada, and recently rooted my phone with a rooted image. I'm comfortable with using CMD / ADB on Windows, and have been rooting many devices for years. Everything was fine. Used it for days.
Even though my bootloader is locked, I read that I could install Xposed via Flash Fire (in this thread). I did it, and things got a little wonky.
My phone would be fine for hours, and then the screen would get corrupt. I'd see coloured static, and visually everything would break. If I pulled out the battery and put it back in, it would boot up fine.
Over the past few days it started happening more often, until yesterday the phone was basically permanently unviewable.
Now, when I turn the phone on, the screen lights up but stays back. I can't see the boot animation. Nothing. Just a black screen.
The phone boots up fine. I can hear the booting chime. It brings me to my lock screen, and I can feel it vibrate as I enter my password. It receives notifications. It responds to ADB. But for all of this, the screen is black. It's on. Lit. But black.

Any help? Any ideas? It's hard for me to troubleshoot, as I can't ever see the screen.