There is an issue with your iPhone's ability to use Face ID
[Re-Titled by Moderator]
Question marked as
Top-ranking reply
If the display is broken, you'll need to have it repaired at an Apple store, but more then likely if the front facing camera is broken, you're looking at a whole unit replacement as that part can't be repaired. It's part of the camera body and depending on the model, you'll have to replace either the whole unit, or the rear glass assembly.
Make a Genius Bar appointment so they can assess it.
Also if you don't have applecare prepare for a cost of 400-600 depending on the model.