Phone screen completely blank, phone itself works

I dropped my Pixel 3a a couple weeks ago and broke the screen (physically fine, but showed white static for ages; then displayed properly, but touch wouldn't work).

I attempted a self-repair and completely exploded the old screen because I am dumb, but I got the new screen connected and it worked perfectly - turned on, displayed crisply, touch worked, yay.

But when I came back to it the next day, the screen was completely unreponsive, and still is. The phone seems to work normally - chimes when I plug it in for charging, makes notification noises, is detected when I plug it into my PC - but the screen just doesn't work, even though it worked fine when I attached it, and I didn't move the phone at all between the time it worked and the time it stopped.

I've tried shining a bright light on the screen to see if it's a backlight issue, but I can't see anything displaying even then. I've also detached and re-attached the screen, and restarted the phone multiple times; again, no dice.

I can only presume I've broken the replacement screen somehow, though I'm sure I was super-delicate in handling it. Does anyone know anything else I could try, short of buying a second replacement screen and trying again? Cheers for any help.