Hi Kellie,
Thanks for getting in touch to the community about your Surface Book login problem. I know its frustrating when you lose access to your device especially if facial recognition was just working but I'm here to assist you.
Sometimes a Windows update a camera issue or a driver problem can cause Windows Hello to stop working and ask for a PIN if you forget your PIN it can feel like you're locked out.
I suggests checking if you're using a Microsoft account or a local account. If it's a Microsoft account try resetting your PIN from the login screen by choosing I forgot my PIN. If that doesn't work restart your Surface and enter the Windows Recovery Environment to access recovery options. To get into Windows Recovery Environment (WinRE) on your Surface shut it down. Then hold Shift and click Restart on the login or Start menu. Windows should boot into recovery mode where you'll see options to troubleshoot, reset your PC or use advanced tools. You can then reset your PIN restore your system or enter Safe Mode.
If you're using Windows Hello for Business your IT admin might have enabled PIN reset policies or Group Policy.
To better assist you, are you logging in with a Microsoft account or a local account? Also, did your device recently update or restart before this happened? What specific surface model were you using and does it run in windows 11?
I hope this answer is helpful, if you have further questions, feel free to reply back
Regards,
Marcelo