Screen is completely black, but phone still functions

Hi,

I found this website after extensive search on the net, I haven't been able to find a decent answer to my problem.

So basically, during work, my 6P (which was working absolutely fine before work) was in my pocket the whole time. After I had finished my shift, I decided to make a call. The problem being however was the fact that my screen was completely black.. but the phone still works? Now you might be wondering how do I know my phone still works, well I tried to see if I can still be able to turn on and off the torch light of my phone which is in the notification bar (using photographic memory) and it worked! So my problem lies in the lcd, but where? Thanks for responding ^^