Can you see the pencil and paper icon above your post..to the right? Click on it and anytime within 30 minutes after posting, you can correct or delete or add to a post.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .