Where are you reading that this model has Gorilla Glass? I'm not sure it does. Nevertheless.
Are you saying the full glass cover is cracked?
I'm not familiar with the make up of this model but if the screen won't work then the LCD is also damaged [which is not the glass cover].
If in fact the LCD is damaged then the whole panel [plus the glass cover] would need to be replaced as these days the LCD and digitizer are glued together. They can't do that in the store.
But you do have a few options. You can hunt the web for replacement parts - if they exist. Try and get a replacement [if you got insurance from Tmo] or send it in to an online phone repair place. In all cases, you might want to just pull the battery and keep the phone off since you can't use it.