Concussion After Effects What Are The Effects Of Dehydration On A Concussion?

What are the effects of dehydration on a concussion? - concussion after effects

I do the research for a story I plan to write, but there is a point that I can not find it. In my story, a character ends with a concussion - nothing too dangerous, but serious enough to cause nausea and vomiting. For this reason, the characters do not drink that. What if you are dehydrated? What are the physical effects of being? And we need the hospital?