Oh poor baby! I'm glad they're going in so they can remove whatever is in there and she can get on the road to recovery.
If it's any consolation, I'm imagining her going through all this in her little necklace - stylish even while under the weather. I hope you get some good news soon!
One of my pugs had this. She had eaten a piece of toy and we never knew. It was very scary, but she did really well. She came though surgery great. She had her stomach stapled up and stayed overnight until she was eating, then came home with a cone.
I hope it all goes well! I know how stressful it is. I cried that whole day.