Bad Smell,is It an Infection?

A bad odour can be a sign of infection, therefore you should see your surgeon if you have this concern. Dissolvable stitches can sometimes take months to dissolve, but it's best to ask your surgeon when you can expect for yours to dissolve.

Dryness and crusting inside of the nose can also contribute to a bad odor - typically nasal saline irrigations will help with this but you should first be seen by your surgeon

Smoking is discouraged before any surgery because it can can slow down your healing process, but it generally will not cause a strange odor.  Sutures themselves do not cause an odor, but sometimes they can attract crust which can cause an odor.  Crusting is perfectly normal 3 weeks after rhinoplasty and can cause a strange odor up to two months after surgery.  Infection is rare in the nose, but I would call your surgeon to make an appointment so he can examine you and answer any questions you may have.