How To Treat Concussion Leading To Vomiting,diarrhea And Loss Of Appetite?

My 3 year old daughter was hit in the forehead with a baseball bat by 5 year old on Wednesday....early Friday morning threw up...has been running a low grade fever of 100 as the max. Loss of appetite, has had diarrhea once, but can t keep anything down when we can get her to eat. Coherent as usual, just mopey.Concussion???