What made it unsuccessful? Did something go wrong, or did it not give any results?
Some pain is expected after, but without knowing why it was unsuccessful, it's hard to say if it's normal or not. Has the doctor examined her?
https://www.mayoclinic.org/tests-procedures/lumbar-puncture/about/pac-20394631
https://www.cancer.ca/en/cancer-information/diagnosis-and-treatment/tests-and-procedures/lumbar-puncture/?region=on
https://www.hey.nhs.uk/patient-leaflet/lumbar-puncture/