Stuffy/runny nose for months!!

My baby is four month old and has been having stuffy/runny nose with mucus in it for three months now. His doctor keeps saying “it’s fine and normal, it will go on it’s own”. It will go on it’s own when!?! It makes my baby breath funny and people keep asking me “what are you giving him for his nose”. How can I be giving something when I don’t know what to give! Please advise me??