Hello, I'm Dr. Deb and will do my best to help you today.
I'm sorry for this concern about Holly. It's actually not uncommon for these smaller dogs to become a little (or a lot!) fussy about getting them to eat.
If she's back to normal in terms of vomiting and her energy level but just doesn't like the food you're offering her, then I would mix different foods together to see if she'll find it more appetizing.
I'm hesitant to suggest that you start feeding her human food such as boiled chicken or hamburg since she may decide to reject dog food altogether in favor of this more desirable food but perhaps mixing it in with her normal food may help get her to start eating it.
I might also consider canned dog food if you're currently feeding her dry....or another flavor since she may be bored with what you've been feeding her (there are a number of different flavor options available these days).
There are also canine sauces which can be purchased to drizzle over food which is often more appealing than just the food itself.
Yogurt is another good option which won't necessarily cause her to reject dog food but may just "spice" up her regular food so to speak so that she has more interest in it.
I hope this helps to provide options for you to consider. Deb