You applied 24v to either the thermistor or the z minimum endstop connectors, which probably blew up the small fuses on the rambo, one controls motion and the other controls accessories, like the lcd. The larger 15a automotive fuse controlls the bed and should be undamaged. The concern is that depending on what you shorted, you may have also blown up the thermistor too. The heater core is less likely to be damaged, but it may have arced and damaged it’s casing or internal element. To test the fuses pull them carefully from the Rambo (it is possible to accidentally pull the circuit contacts and destroy the board, I found that out the hard way once) and use a multimeter to measure resistance. You can look on YouTube for a fuse multimeter tutorial if you like.
The dark lcd is almost certainly the fuse or the Rambo board. There wasn’t enough voltage to burn yhe back light most likely. It’s quite likely the thermister may also be damaged if that was what you shorted to. You can test it also by measuring resistance, the proper values should be somewhere in this forum.