The only way to get unblocked is to ask that person to unblock you. You can create a new account, but wouldn't they just block you again?
For a long time people that you blocked on Facebook could still message you if you were friends before you blocked the person. I *think* this has since been fixed.
If this person was blocked, and now is no longer in your blocked-list (ie, he has become unblocked) then i have no idea how that could happen - but, you can simply re-block him.
You ask your friend (via email, txt, telephone, or, in person) to remove the block.
when they accept you as a friend, then your messages will no longer to to the "other" folder.
If your account is blocked there is nothing you can do to get it unblocked. You could create a whole new account but my guess is that as soon as the person realizes it's you, they will just block that account too.
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