My name is***** and I am sorry to hear that Jada is sick. I am also sorry that no one has replied to your questions until now, so I hope that I can help you and her this evening.
Vomiting in dogs can be caused by numerous different causes. They can range from dietary indiscretion (eating something they shouldn't), kidney or liver problems, intestinal obstruction, cancer, inflammatory bowel disease. Vomit appearance can range from bile (yellow foamy stuff), to partially digested food. At worst it can be pink to red because of blood from the stomach. (This said, I do not think the acorn poisoned her).
Acorns are definitely very irritating to the stomach and can cause vomiting in dogs. I would wonder if Jada ate the acorn and this caused severe irritation to her stomach that caused prolonged vomiting. The other problem I see is that dogs will vomit, become thirsty and drink a large amount of water (which irritates the stomach even further) and makes them vomit again. When dogs vomit, I recommend removing the water for at least 4-8 hours to allow the stomach to calm down before allowing them to have a small amount of water.
I don't recommend promethazine for Jada because dogs are very sensitive to these types of drugs. They can cause low blood pressure and intense sedation.
If Jada is still vomiting, in spite of removing her water and food for 12 hours, then I would recommend taking her to your regular veterinarian. They will likely recommend blood work and abdominal x-rays to ensure that she does not have an intestinal obstruction.
If she is no longer vomiting, I recommend starting her back on bland food such as boiled chicken and rice for a day or two and then transition back to her regular dog food.
Good luck to you and Jada!
I hope this answer helps you. Feel free to contact me if you have any further questions.
Kansas State University
College of Veterinary Medicine Class of 2001