Thanks for posting your query here.
You've not mentioned her age.
From the description given about possibility of momentary loss of consciousness
and now getting headache (never had one like this before) - I would advise to see a doctor for full check-up. She may need a CT Scan
of her head to rule out anything worrying, but that decision will be based on the examination findings.
She can take simple pain killers like Paracetamol
in the mean-time for her pain.
Hope she recovers soon.
Dr Tejas Shah