Face ID worked, then stopped working when I closed iPhone

Hey,

I just did my first ever iPhone screen replacement on an iPhone 12 Pro Max. Everything went great apart from one thing.

I was told to be careful when moving the Face ID sensor to the new screen. I did the swap, and Face ID was still working on the new screen. I tested it several times while the phone was still open, and it worked perfectly every time.

Later, I closed up the phone, turned it on, and tried Face ID again. This time, it didn’t work. It gives me the error that Face ID is disabled, or something like that.

At first, I thought maybe I had misaligned the sensor or that the screen was overlapping it in a way that caused interference. But then I reopened the phone and found that the proximity sensor cable had a visible cut.

What could have caused this? Could the new screen (a JK LCD) have put pressure on the cable when closing the phone? I don’t think the sensor itself is damaged since Face ID worked fine before closing everything up. What should i do the next time?

Any advice would be really appreciated.