Hey there shrv_eel,
Thanks for reaching out to the Apple Support Communities. To get started, are you seeing an alert showing that your Face ID has been disabled on your iPhone? If so, check out the steps in the following resource that can help: If an alert says Face ID has been disabled on your iPhone or iPad Pro - Apple Support
What to do next
1. Update your iPhone or iPad to the latest version of iOS or iPadOS.
2. Check if there is an issue with Face ID in your iPhone's parts and service history. To do this, open the Settings app, tap General, then tap About.
3. If you still can't enroll your face or unlock your device with Face ID, you can take your device to an Apple Store or Apple Authorized Service Provider, or contact Apple Support about your iPhone or your iPad.
Only a trained technician should service your device. Improper repair, modification, or use of nongenuine Apple components in the laser systems might prevent the safety mechanisms from functioning properly and could cause hazardous exposure and injury to eyes or skin.
What the message means
Using diagnostics available in iOS 14.6 or later, Apple has detected an issue with your TrueDepth camera that might cause it to not function as expected. The TrueDepth camera contains lasers, which might be disabled for safety reasons if the device malfunctions or is damaged. This won't prevent you from using your iPhone or iPad, but until your iPhone or iPad is updated or serviced, you might not be able to use Face ID, Animoji, Memoji, and some other features that use the front camera.
If you are seeing an alert showing your Face ID has been disabled, and the issue persists after going through the steps above, it is possible that the issue may be hardware related. If that's the case, the next best option would be to have your iPhone inspected further in person and possibly serviced. For help with finding nearby service locations, check out this next link here: Find Locations - Apple
If you're not seeing an alert showing that your Face ID has been disabled, and Face ID is not working as expected, take a look at the steps in this additional resource that can help with troubleshooting the issue further: If Face ID isn't working on your iPhone or iPad Pro - Apple Support
We hope that's able to help.
Have a great day!