I actually came on to respond to someone elses question with this same response, but i think it may apply to you as well.
I was with a friend yesterday and she is training to become a midwife. She told me a story she learned in a class about a little girl who was afraid of an old fashioned painting of a woman with a pearl necklace on. she would point at it and say scary. The little girl had been born with her cord around her neck, and when the mother asked the little girl if she remembered her birth and how the cord was around her neck, the little girl put her hand to her neck and pointed at the picture and said 'scary'. the mother acknowledged that the child had been afraid, and after that the child was fine. i believe she wasnt actually afraid of the picture, she was trying to get her mother to acknowledge her frightening sitation.
after learning about this, my friend tried a similar thing with her son who had a traumatic birth and was afraid of physicaly challenging things. she talked to him about his birth and said she was sorry it was so scary, and the next day her son was no longer afraid.
my friend said that when a baby cries and is inconsolable, they are just trying to tell their story.
it may be that your child is trying to tell you her scary story of when she fell and hurt her head. maybe if you talk to her about her frightening experience and just acknowledge it and show her empathy she will feel better.
it could be that she is physically fine, but emotionally upset. i hope you find this helpful. i just had to share this amazing story. and i really hope your baby does not have any physical damage. i know being a mother is often frightening and worrisome.