You can easily unblock someone on Facebook Messenger in the "People" preferences section of the app. Here's how to do it.
These days, after meeting someone in person or online, the first thing you might do is look them up on the internet. At some point, you've likely scrolled through a new connection's social media pages ...
Culling your friends list is one of the things you need to regularly do on Facebook, if only to ensure that you only interact with people who matter to you and not be inundated by irrelevant life ...