Switching from one FB account to another. Help please.

I accidentally logged into CoC using someone's FB account. Though the FB account i'm actually using is synced into my tab. I did almost everything, uninstalled FB, disconnected FB in CoC, then reinstalled, then connect FB in CoC, blah blah... Still the previous FB account, where I was first logged-in, shows up. I can't think of ways on how to switch from one FB to another. Main reason why I'm being so eager is... I can't reach out to my FB friends who're playing CoC. Help me please(i'm using Android btw). Thanks. :o