Very nice ragged perforation error. I believer they are only called blow holes when they are not touching the edge of the coin. Great find though!
I would call it a "ragged notch", but it arises in the same manner as a ragged clip, ragged perforation, and ragged fissure.
Looks like a blowhole that happened near the edge. I think they call that a ragged edge clip or something like that. Sort but I’m not thinking too clearly yet. Nice error coin so protect it.