Hello I’m having a problem with my Face ID

if u remember the passcode to unlock the device, go to FaceID settings. To get in, it will ask for the passcode. After inserting the passcode u can enter the settings and click on Reset Face ID.

See if anything here helps 

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.    -

Fix iPhone X Face ID Not Working.    -

Face ID Not Working.   -