Hi, Last Night My Wife Hit Her Head On The

Hi, last night my wife hit her head on the corner of an open cabinet door. She hit it so hard that while standing it almost knocked her unconscious. She had a headache afterwards and all day today, and about one hour ago reached up and felt a dent big enough in diameter for me to put my middle finger in. Personally I thought anytime something indents instead of swells it's not a good thing. Not sure how concerned we should be. Thanks