How do I get my Face ID back

Click ▶︎ Face ID not working.

If that didn’t work, then try deleting the Face ID profile and adding it back.

If that didn’t work and there were no error messages, then get live expert assistance by contacting Customer Support by phone or chat:

• Call Apple Support at 1-800-APLCARE. 📞
• International Support. 🌐
• Contact Apple Support. 📝
• Chat using Messages. 💬

See if anything here helps 

Face ID on your iPhone or iPad Pro.  *

Face ID - If an alert says has been disabled on your iPhone or iPad Pro.  *

If Face ID isn't working on your iPhone or iPad Pro  *

Face ID not working.   -

Face ID not working' problems on iPhone.    -

Face ID Not Working.   -

You also may need to take it in for service.

Genius Bar Reservation  -  US.    

Find a store.  -

Authorized Service Provider.  -

ASC YouTube for how to to schedule a repair at an Apple Store or Apple Authorized Service Provider – Apple Support