I'm sorry to hear that you're having issues with your iPhone 12's Face ID. Here are some troubleshooting tips you can try:
- Make sure that your iPhone 12 is running on the latest iOS version. To do this, go to Settings > General > Software Update.
- Check if there's any dirt or debris on the front-facing camera or TrueDepth sensor components. Use a soft cloth to clean them.
- Disable and then re-enable Face ID. To do this, go to Settings > Face ID & Passcode, enter your passcode, and then toggle off Face ID. Wait a few seconds and toggle it back on.
- Reset Face ID. Go to Settings > Face ID & Passcode and select Reset Face ID. Follow the prompts to set up Face ID again.
- If none of the above steps work, it may be a hardware issue. Contact Apple Support to assist you further with this problem.