When a user blocks you on Facebook, they sever the connection between the two accounts entirely. From Facebook's perspective, the relationship does not exist. You do not have the authority to manage their privacy settings, which means you cannot "unblock" yourself or reverse their action.
How to unblock myself when a friend has blocked me on Facebook how to unblock someone who blocked you on facebook
If you have a legitimate reason to speak with this person and it is an emergency, use a different channel (text message, phone call, email, or another social media platform). When a user blocks you on Facebook, they