It may be coincidence rather than the muffin batter from Friday night, especially as you said it was only a few drops. Don't think it was the blueberries in it either. Dried blueberries are one ingredient in some holistic dog foods and dog treats, for the antioxidant benefits.
Any suggestions on safe hydrating things I can give her that is safe for dogs obviously. I am afraid she is getting dehydrated.
Pedialyte is safe for preventing dehydration, even safe for cats which have much more sensitive systems than dogs. But check with your vet
first for your dog's specific breed. If the vet says it's OK then you can use an animal medicine syringe. If she's refusing liquids you drop it into the dogs mouth a little at a time, don't shoot a whole bunch in at a time or she can aspirate it.
But that's for dehydration prevention only ... if you think the dog's dehydrated already then take her to the vet ASAP!! You said this has been going on since Friday night and said she's "still refusing food and water" ... an 18 lb. dog can dehydrate quickly.
One sign of dehydration is if when the scuff skin is pulled up it stays up. Depending on breed it should either snap right back or go back into place pretty quickly. If it stays up and doesn't move, please bring the dog to the emergency vet. Scruff skin that doesn't move back down means the dog may need IV fluids. Sorry ...not trying to scare you, but dehydration is nothing to fool around with ... it can get pretty serious.
*hugs*