Just want to know, what will you guys do when meet this problem ?
Yesterday night, I turn on a game and I just leave it, ( because keep chatting on pc ) then it will auto turn off after the sleep time reach, but after that I can't turn the screen on by pressing any button. Then I decided take out the battery, but before that I keep press the power button and home button ( long press, short press ) then lucky it turn on back.
But when the screen blackout it got warm on it like still turning on and not full off.
Is it any trick or way when meeting this kind blackscreen because of application or any other problem that can force to off the S3 and turn it on back ?

Is a normal seal line for the case.
When I get my phone also see this line n try search online for those S3 user picture to double check.