Hello There,
Thanks for writing in!
All you need to do is add yourself as moderator under Facebook developers comments tool. That’s it, you’ll start getting notifications of any comments on any of your blog posts.
Open this url (am assuming you are signed into Facebook and is administrator of your Facebook app):
1) https://developers.facebook.com/tools/comments/
2) Click on settings
3) Add yourself as moderator.
For more information you can walk-through following documentation:
https://developers.facebook.com/docs/plugins/comments#moderation
Thanks.