Rigify can't seem to generate my rig because of an issue relating to the nose. It says "bpy_prop_collection(key): key "ORGnose" not found. Which is weird if you ask me because there are nose bones placed on Van's face (The character)
You probably deleted bones from the face. Rigify needs all of the facial bones to generate the rig.
Or you may have disconnected some of the bones that need to stay connected.
I have made a video about the face rig https://www.youtube.com/watch?v=n8aCBKjPJRE
There is also a whole playlist of videos where I tried to explain how to avoid most of the annoying errors that Rigify throws at you. https://www.youtube.com/playlist?list=PLdcL5aF8ZcJv68SSdwxip33M7snakl6Dx