Hello, This is likely a viral upper respiratory infection infection ; these can last 7-10 days. I would call his treating pediatrician againIF cough starts new or any trouble breathing, he is not drinking enough to stay hydrated, he acts totally listless or way too irritable, or you are worried and not comfortable with how he looks / acts.
Please post back if more questions.
HSV can cause runny nose and throat ulcers.
I have been treating him with Tylenol round the clock for going on 6 days now... Should I continue and is this harmful to his new developing liver??? Thanks!