Sounds like there are 3 possibilities.
1) you either did irreparable damage to the LCD itself
2) you knocked the LCD cable loose -- the digitizer, sensor for the pen, and the LCD all have their own connectors
3) you damaged the cable to the LCD
I would check to see if all the connections were firmly plugged into the logic board.
If they are, and it still doesn't work, your best bet is to replace the entire assembly.
http://www.ebay.com/itm/OEM-Samsung-Galaxy-NOTE4-LCD-Screen-Display-Touch-Screen-Digitizer-A-/152465386746?hash=item237fa52cfa:g:2EgAAOSwTM5YwIzE