Bad cough after rhinoplasty?

I had a rhinoplasty 3 weeks ago and since I had the internal bandages removed after a few days I've been coughing non stop!....A really bad cough and my nose feels a bit stuffy....I can't take it anymore..I might be paranoid but I'm an amateur singer and the last thing I need is even the slightest damage to my throat..I can't even sing anymore,I end up coughing!.The doctor gave me a syrup,I'm using a spray for the throat as well but nothing!...It won't go away....What the hell is this? =_=