If you feel that you may have been the victim of a Facebook phishing scam, the first thing you should do is change your Facebook password. If you’ve linked your Facebook account to other online services, it would probably be best to change the passwords to those services as well.
Follow these steps for removing scam facebook app:-
1.If you’ve granted permission to an application, you can revoke permission through your privacy settings. Navigate to your Privacy Settings, and at the bottom of the page, click ‘Edit your settings‘ under Apps and Websites.