Why isn't my screen displaying?

First off, I am 12, I just wanted to put that out there. A while back I had replaced my Iphone 4s screen and it was unresponsive to touch on one half of the screen and fully functional upon the other. So, today I took it upon myself to try and fix it because I am stuck with the slow Iphone 4. I was toying around with it and was just taking apart the phone and then I tried plugging it in after I had thought everything was assembled and now there is no display on the screen whatsoever and I found out that when I press down on the part of motherboard/logic board where it has a sheet over it reading "Authorized service provider only", it will vibrate every now and then, also it is unusually hot in the same area. Please Help me maybe? I would greatly appreciate it :)