iPhone 6 dead after screen replacement

I was trying to replace my old screen for a new one.

Here's what happened:

I was being guided by a YouTube video. The main thing is the guy DIDN'T tell that we must disconnect the battery before doing anything.

So I removed all the old screen and its components and put in the new one.

Once everything was in place, I started to plug the cables back. There was 4 of them.

When I was plugging the second, which I believe is responsible for the backlight, I saw some smoke coming from the connector. My heart stopped. But the smoke stopped and I continued with the connections. When everything was place I turned the screen on and... nothing happened. But the phone was working, because i connected to the carger and i heard that sound of charging.

So i put the old screen back just to check if it wasn't because of the screen, and nothing happened as well. I tried to clean the connectors... well, everything. Nothing solved my problem.

No i have a dead phone. It gives me sounds, like the charging sound, but i can't see nothing.

Just frustating.

I could have avoided all of this if that guy just have told how importante it is to disconnect from the battery.

Anyways,

is there anyway to repair that damage or would be better to trash it into the bin?

thanks guys..

These are from now.