Usually within 72 hrs of intake of antibiotic clinical symptoms started to improve. Monitor the temperature chart and see whether any decrease in frequency or severity of fever is there or not. Cough usually takes time to resolve. In the presence of respiratory of respiratory distress
go for chest X-Ray to rule out other cause as acute bronchitis
usually manifests as cough and fever. If he is still running high grade fever then consult your doctor for proper laboratory ( like CBC, widal
,throat swab, blood culture
) and clinical evaluation to rule out other causes.