most infections in the sinuses are viral and not bacterial so penicillin would not likely help in this case. i do not know that how you were diagnosed with strep. unless you had a lab test to confirm it you may not have strep at all. a visual diagnosis is wrong about half the time.
can penicillin cure a sinus infection? . yesterday i was diagnosed with strep and put on penicillin. however i am still struggling with congestion and a bad cough which i think may be sinus related. do i need to go back to the doctor for another medication?