Hello kamran31,
Welcome to Apple Support Communities. We see from your post that you've encountered an issue with Face ID, and followed the steps here to try to resolve the issue: If Face ID isn't working on your iPhone or iPad Pro
You've done great work so far! We suggest completing all the steps in the article you viewed, including those under 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" follow this link to Get Support directly from Apple.
We trust these tips help you to resolve this ASAP so you can enjoy the convenience of Face ID again.
Kind regards!