Hello there welcome to HCM, Well headache is not uncommon after any trauma to the head(direct or indirect) even though its been 3 days still your girlfriend needs a thorough check-up as well as neurological assessment There s not enough details provided specially you didn t mention how did she hit her head, wheather she s having any other symptoms apart from the headache(i.e. if feeling like throwing-up, any problem seeing things, feeling sleepy lately etc.), any weakness in any part of body You did mention though the Headache is highly unusual for her - so did she experience any headache previously also(before the injury even occur) Well I need to know which kind of pill (specific name? or over the counter?) then only can opine some thing bout that well I certainly appreciate your concern as well as double checking but its highly recommended that you take her to your nearest ER/neurologist to get her thoroughly evaluated regarding this as soon as possible and let me know what happens next.. Once again thank you for seeking help to HCM, hope to get the updates soon