Pulled too hard when opening iPhone. Did this kill my iPhone 5 screen? So I bought a replacement home button for my iPhone 5. I tried to gently lift the screen with a suction tool, but when it finally lifted, it yanked something off and now the screen won't work :(

I took my phone apart twice, back to back. I successfully reattached the 3 cables and the screen was working fine.. I reassembled and realized I forgot to remove one of the adhesive backings, so the new home button wasn't working. When I took it apart again is when something pulled with it. I fixed the button and tried to reconnect the 3 cables again. But the screen remains  black :(

I have no idea what the part is or how to fix it. I hope I didn't just destroy the screen! I found a picture online and edited it to show the part that pulled off from the backing. Please help meee!
iFixit has a great guide about the disassembly of the iphone 5. All courtesy of the pictures goes to them. Step 11 clearly demonstrates the ribbon cables . 

I highly suspect that you just yanked a little bit too hard on the LCD cable and hence the black screen. I am in no way affiliated with iFixit but I recommend the use of the iSclack opening tool. It only lifts the screen as much as it needs to preventing you from breaking the delicate ribbon cables.