You may want to disassemble the phone enough to be able to check its connections on the motherboard. It is possible that the displays connection was loosened when it was dropped. Try reseating the display's cable connections and see if this fixes the problem. You may also want to look over the cables and other parts for damage.
If reseating the connections still leaves you with a black screen then may have broken the LCD in the display. To fix this would require a new LCD or new display assembly(LCD ➕ digitizer) if the digitizer is damaged too. The digitizer is the part of the display that is responsible for sensing touch. Hope this is helpful.