Poor girl - neck sprains are no fun.
I've had two dogs do this and they were better in a day or so, so I'm hoping Zuki is back to herself by today. The homeopathic remedy Arnica (30C potency) is always my first choice for injuries - bruising, trauma, sprains and strains. You can give this a few ways - drop 3 pellets in the back of the mouth/flews, crush the pellets between two spoons and then sprinkle the powder on the tongue, or dissolve the pellets in spring water and give a dropperful. You want to give the remedy at least 30 minutes away from food.
Here are some articles about homeopathics and other options for pain/inflammation, the last specifically for pets: