What would you have done?

I'd just keep it to myself honestly, and make sure your sister keeps it to herself, too. Don't let either of your parents know because it could start to get NASTY. No one can hold a grudge longer than a family member, because that hits deep.. family is all you have and if they defy you, who else do you have to turn to?.. You know? If your parents know it will get back to all of your other family members too and just enrage the feud. If your grandma brings it up again, I'd just be more assertive and somewhat b----y and guilt trip her back about how that made you feel especially when she is living in YOUR house and she's lucky you guys let her leech off you (except.. word that differently, lol.) Also make a rational point about how you really do love her and that's unquestionable, and to not even try to manipulate you on that fact.. point out to her what she was blatantly doing to you. Stand up for yourself and your family, but don't let it get too out of hand or emotionally responsive.