Mysterious iPhone black screen

So I have this iPhone XS and when I’m Using it the screen sometimes goes randomly black. you can feel that it’s still moving around but you can’t see anything on the display the only way I was able to turn it back on was heating it with a hair dryer so that it overheated and rebooted but in a matter of hours it was black agian.

I was thinking it’s either a screen or battery replacement but I just need some confirmation