Strep throat

Our 5 year old tested positive for strep throat on Wednesday, his doctor said he is cleared to go back to school after 4 doses of the amoxicillin (which would be Friday). I didn't send him Friday because he was still coughing. He doesn't have any other symptoms at all. Just a rough sounding cough. Is this typical for strep throat? Should I send him back to school tomorrow? It's our first round about with this!