How do I approve a follower request?
If your account is set to private, anyone who wants to see your photos or videos will have to send you a follower request that will appear in your News.
To approve/deny the request, just tap the username of the person who requested to follow you. You'll be brought to their profile and at the top of you should see the Approve and Deny options.
If you accidentally deny a follow request, ask the person to request to follow you again.