Why is my screen black, but everything else works..

my screen black but i didnt drop it in, no liquid spill on it.

after taking some pictures around, i used it as torch back to the camp site. i turn the torch off and put down on the table, after a while when somebody asked me to send those pictures i get my phone and found out it was black, i thought i turn it off when torn off the torch. but, the led indicators blinks when my message tone beep..

i still can receive calls, used my torch and even play music, everything works properly except the lights on screen.. when i`m on my room and turn all lights off i barely see all my apps.. i don`t know what happen, why screen goes black, please help.. thanks