If you're using Chrome:
Click on the icon in the top right hand corner (the one with 3 little dots).
Click on settings.
Scroll to the bottom and click on show advanced settings.
Scroll down to passwords and forms and click on manage passwords.
Scroll down to facebook in the list and click on the starred out password.
You now have the option to click "show", which will show your password. You might have to input your laptop's admin password, depending on what level of security you've got set.