Hello Sallison1984,
Welcome to Apple Support Communities!
It sounds like you’re having trouble setting up Face ID on your iPhone. We’d be happy to help.
We see you’ve already checked out If Face ID isn't working on your iPhone or iPad Pro.
Is anything obstructing or covering the front TrueDepth camera? Do you have a case or a screen protector on your device? If so, it might be helpful to remove it if you can and then test to see if you can set up Face ID.
Did you follow all of the suggestions in the resource above? If you did and the issue resumes, take a look at step 8, “Reset Face ID.” “If you can’t enroll your face, take your device to an Apple Retail Store or Apple Authorized Service Provider or contact Apple Support.
Take care.