Crikey that must have been scary for both of you, people seem to leave all sorts of things about from salad food/peanuts/pumpkins (when in season) in an old tree, old bread on open grass and all manner of other horrible stuff.
Pleased to read Hattie is non the worse off - but it would have been worrying for you to see her like that.
As for social media, well I guess you will always get people who think they know better and are willing to contradict whatever the subject. Thank goodness you and the vet are on the ball, that is most important.