I agree, the shaking is of concern. Most dogs stop eating for a day or so after ingesting something that doesn't agree with them. It is best nbot to feed anything for at least 24hrs to allow the digestive tract to calm down and return to normal. However, tremors (shaking) is very unusual, and could indicate something other than the obvious, so do take her to the vet straight away.
You have to use Peroxide pretty soon after injection.
Agree with Jaybay. I would be more concerned about pancreatitis and that is nothing to mess with.
I'm more concerned about the shaking that's happening with the bloat. That's not a typical upset tummy and forcing vomiting may not be the best thing to do at this point. I'd be looking for an ER vet tonight.
At the extreme, if she doesn't vomit it up, a cap full of peroxide will induce vomiting.
If you do go for this, use an eye dropper or turkey baster to make sure she drinks it. After she does go out on a long walk and try and get her to run. That will get the peroxide going and she will vomit. After, I would give her a bit of Pepto bismal then a bland dinner of cooked rice and boiled chicken.