How to log out of facebook without my phone?

[Ethan]

I recently got my phone taken away, my mom knows the opening to my phone (the lock screen) and i'm afraid she'll look through my phone for facebook/texts. I have messages between me and a few friends talking about drugs, and I don't want her to find out. I don't want to hear about how bad drugs are, etc, I just want to know how I can prevent her from finding out. I can't log into facebook from home because that's also taken away, and my school blocks it. I know there's a feature where I can disconnect all phones from facebook but I can't get in it.