Jordyn-
I'm sure you've taken care of your bird already but absolutely keep any paper product away from it as mentioned in an earlier post. It will dry the bird out.
My taxidermist used to have Subway sandwich bags in his shop, you can slide the bird right in head first and then double bag it afterwards. If you brought the bird in packaged in a way he didn't want, he'd put it in the Subway bags when you brought it in. I keep a bunch of clean bread bags handy just in case, they fit ducks pretty well.
As far as getting the bird to the taxidermist as fast as possible, that will only help out how quickly he gets it back to you. I've had my birds at my taxidermist for over 1-1/2 years a few times. He usually doesn't take that long but every now and then, he does. Guess what? When its at the taxidermist, it sits in the freezer too!

I've honestly got a Bufflehead in MY freezer that I shot last year that I still have to bring in. I'm not worried about it.
Nice Bird BTW!