There is no unlock function provided, that Lock function is to protect your data if your device is lost or stolen, the only way to access that device now will be to reset Windows.
If you have data on that device and do not have a backup or use OneDrive to sync your files online, try using this method to backup your files to a USB drive before resetting Windows.
Click the power icon on the Login screen.
Press the Shift Key and click Restart
Your PC will boot into the Windows Recovery Environment
Go to Troubleshoot - Advanced Options - Command Prompt.
In Command Prompt, type Notepad.exe and press Enter.
Notepad should open,
In Notepad select File - Open.
You may then be able to use the Open File dialog like a small File Explorer window to copy out your files and folders to a USB drive.