Hello, My Daughter Age 19yrs Fell Hit Her Head On

Hello, my daughter age 19yrs fell hit her head on a metal bar got knocked unconscious, she had been drinking on a night out. 2 months ago, she did go to hospital and she had severe concussion.
My daughter has just had an eye test and her pupils don't dilate when a light is shone in her eyes.
They would like her to go to hospital, what could be the problem as she was discharged when she hit her head they did not check her eyes.

Many thanks clare