The touch is not working

I have the same problem. I was trying to replace my friends iphone 4s screen (cracked) and I took it apart but then realized that the screen replacement was missing the LCD (just the front cover glass). So I put it back together and I know the first time I realized that I didn't pull the display ribbons all the way through because they couldn't reach the connections. So I dismantled it again to fix it and put it back together and it turns on and works but the touch is not working. Do you think just need to get a new screen to get it to work because the digitizer ribbon maybe damage? I tripled check to make sure all the connection were good and they were.