What did I miss?

No, that was the only freebie. The premium items for purchase are still available for about a day and a half.

Have you completed the questline for Milhouse's new skin?

I did get the Milhouse skin but I don't think I'm done with the Ralph quest. I've had the kind of fever that makes you a bit loopy so I don't even remember where I left off lol.
I appreciate the replies; I was worried I'd miss out on a lot of stuff being sick on Valentine's Day.