This will improve and heal over time. The amount of time depends on the injury itself. Symptoms generally fade, but on the good days make sure that she keeps resting and not doing the things that agitate her symptoms. At this early stage (and yes it is very early in terms of a brain injury) your daughter needs to avoid things which will work her brain too hard. This means watching tv, concentration, smart phones and places where there is high stimulation for the brain. Avoid sugar heavy foods and foods with sweeteners.

Other things to do is not to worry and stress about this. Stress makes symptoms worse. Get a regular sleep pattern and naps during the day if required. Research vitamins, they can help not only alleviate symptoms, but also help the healing process. She will need you to reassure her, this will help her in her recovery, but I won't lie, it may be some months before she is back to normal, this may not be the case, but nobody can tell. Any questions you have, don't hesitate to post them, there are many experienced people here who are willing to help.

I wish your daughter a speedy recovery.