My 9 year old has strep. he's had 3 doses of abx. still has low grade fever (99-100) and now has developed a headache. should i be concerned?

Strep throat: Treatment of Strep throat seldom treats the disease, but is used to remove the risk of subsequent development of rheumatic fever. Sometimes if begun early enough the antibiotics will shorten the course of illness. If the headache was accompanied by stiff neck, alterations in sensorium or level of consciousness, nausea and vomiting or other symptoms would definitely taken her to a doctor.