True, there was no appearance of fatality... -not to an educated eye at least. And of course that's not the way he told it, is it? No, the way he told it, it was much worse than a simple, bad shaving knick-equivalent grazing.
And, if we look deeper into what may be gleaned from the parable, by the time the Beast appeared the wound was long healed. So, much like your original imputation of non-existant parameters to a question dealing specifically with what is and isn't part of the head, the hoi-polloi witnessed a scar that looked bad and lied to themselves about its nature.