Well, I hope you do not have a dead LCD display that would suck 
You could inspect the eDP connector both ends of the cable to check they have not fallen out (obviously the panel end is difficult to get to -- there are other things you could prioritise to check first, checking this connector only as a last resort before actually buying fitting a new LCD panel). Checking the cable for damage too.
Did you ever use USB-C to HDMI? You could see if there is any video on an external monitor. And if there is, that might help diagnose things.
Remotely SSH'ing in to PBP to check dmesg, logs etc.
You could inspect the eDP connector both ends of the cable to check they have not fallen out (obviously the panel end is difficult to get to -- there are other things you could prioritise to check first, checking this connector only as a last resort before actually buying fitting a new LCD panel). Checking the cable for damage too.
Did you ever use USB-C to HDMI? You could see if there is any video on an external monitor. And if there is, that might help diagnose things.
Remotely SSH'ing in to PBP to check dmesg, logs etc.
