HTC Desire 816 screen not responding

[Daedhro the Elf]

Last week, I was getting into my htc as the back camera stopped working. I got as far as removing the back case, and unscrewing those black plates that are over the top of the boards. I only touched the back camera (did not pull it out just went to check if it was still plugged in). After that, I put it back together and it wouldn't turn on, at all, nor take charge.

Took it to a repair place the next day, turned out my battery plug was a bit loose so he fixed that. It began to charge, but now the issue was the screen. It was something at the bottom right of my screen was playing up (if he gently squeezed it, it'll turn the display on and stuff, so I assume I broke something down there inside the phone). He put some matte sticky tape over the screen (not inside, on the outside) which got it to work for a few days, but now it's just stopped working again.

It will not take charge, and it won't really turn on. If I hold the power button for a few secs, the screen kinda is on but it's just black, then it'll turn back off. I've tried some button combinations but nothing works. Sorry if my explanation doesn't make much sense, I can clarify anything you don't understand, but I was just wondering if anyone might have an idea of what the problem is so I can fix it, or is the phone completely ****ed? Thank you.