Hello, I'm Dr Gary. I've been practicing veterinary medicine since 2007. I look forward to helping with your questions/ concerns.
With drooling and lack of appetite, we usually want to rule out a tooth root infection as the most likely cause. Often this is hard to localize just looking at the crowns of the teeth. Sometimes there will be some redness to the gums, but to diagnose it we really need dental x-rays under anesthesia.
I would first want to make sure there is no foreign material in the mouth. Look at all the teeth and on the roof of her mouth. Sometimes we'll see pieces of stick stuck on the roof of the mouth or pieces of plastic or wood stuck around teeth. These can be removed if found.
If there is nothing in the mouth, then I would rinse it out with water in case it's a taste reaction. You can then try to feed some treats or canned food.
If still no improvement in the next couple hours, then I would get to your vet when they open for a good dental exam and x-rays.
I hope this helps, let me know if you have any other questions.