Display got hot and stopped working

I placed (unthinkingly) my iPhone with the display on a hot surface (LED light that was off but still warm). Suddenly, the display turned off, but not the phone. It continued to be hot (around the area of the display connector) for about an hour, then went normal.

Now, everything is working fine except the display. Touch works etc., I can use Touch ID and Siri, I just don't have any visual feedback of what I do.

I opened the phone and tried a different screen I know to be working, same issue, touch works but backlight doesn't turn on.

Double-checked the display cable and also tried hard-resetting, nothing.

I really hope I don't need to replace the LCD IC, as I don't have any experience in micro-soldering... Does anyone know anything about this issue?