Some hedgies like to lick their nose more frequently than others (trust me, I thought Wonton had a URI too when I read about frequent nose licking). I believe discharge is meant as in a runny nose...? I am not too sure, but I think it's referring to something that drips out of the nose. Sometimes, I find that vets give meds just as a precautionary measure...And possibly earn some extra bucks off you.
I would continue with the meds until the designated date to stop using it, because it could come back!