Suggest Treatment For Nausea , Vomiting And Fever In A Child

My daughter is 4 years old and has been having nausea and vomiting with fever. The fever resolved within 24 hours and the vomiting and nausea persisted on and off for a week. The vomiting subsided for about 5 days but still complaints of abdominal pain in the umbilical area. She was admitted overnight to pediatrics for fluids. xray was completed and showed free fluid in the right lower quadrant, appendix not demonstrated and multiple mesenteric adenitis, with prominent lymph node in the mid abdomen 17x8 mm. They discharged her and told me to continue fluids and it will take time for it to resolve. My daughter has a poor appetite still after two weeks after discharge and continues to complain of abdominal pain to umbilical area with worst pain to RLQ. With deep palpation to the RLQ she bends at the knee. Should I carry her back for evaluation? Does mesenteric adenitis take so long to resolve and can it cause appendicitis?