Brief Answer:
Get her clinically evaluated by a physician

Detailed Answer:
Hello

Thanks for asking on this platform
I can understand your concern. Fever with abdomen cramp can be due to infection in the intestine (colitis),urinary tract(UTI)or in the female reproductive system (pelvic inflammatory disease).
Headache is a very common associated complaint due to the fever itself.
I would like to know the exact site of pain (upper,lower,right or left side in relation to umbilicus)and associated symptoms if any like loose stool,burning micturition or any discharge from the vaginas.
I suggest you to get her clinically evaluated by a physician so that he/she better able to understand and manage the condition.Till then continue giving tylenol.It will help in relieving fever and headache.For cramp you can give dicyclomine after consulting your physician.

I hope this helps.
Please let me know if you have any more query.
Wishing for your child's speedy recovery.
Regards

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Brief Answer:
Can be UTI or PID

Detailed Answer:
Pain in lower abdomen is more likely due to urinary tract infection (UTI) or pelvic inflammatory disease (PID).
Urine examination and or ultrasound abdomen may be needed to confirm the diagnosis and management accordingly.
Regards

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