Answer to: My phone works but my screen is blanki have the note 4 and i always go to the gym with it. i got in the sauna for 10 minutes like i always do but this time the screen got completely black after that. I guess it was overheading or i got some water inside for the humidity. It did nor work for 1 day but somehow it began to work normally next day.. I guess it was a problem because the humidity and as soon as it got dry inside that fix the problem. Hope this answer solves some of your problem. Sorry for my writting.