You just have to buy a digitizer because you have a lcd which is working. But there is a problem, when i dropped my device like you, phone service told me to not to only buy digitizer and i bought lcd assembly digitizer which is on the upper post. So firstly contact to service then order what you need.
Last, as you know, butterfly has different versions. This means you should be sure if the digitizer will fit your device. I had ordered a digitizer for x920d but it didn't fit. Taiwan version of butterfly is a bit longer than the others.
Sent from my HTC Butterfly using xda premium
HTC Butterfly X920D