Is it bad to have smoked after having sinus surgery?

Smoking and surgery: Smoking is not bad; addiction is not a moral issue. Smoking will impair your body's ability to heal.

Not the best idea: Surgery is usually a last resort for anything. If you had bad enough disease that you needed surgery, you should commit to a lifestyle that prevents recurrence of the problem. Smoking significantly increases the risk of issues of the respiratory tract in addition to the myriad of other horrible problems it can cause. Smoking most certainly can affect your sinuses negatively.

Yes: The nicotine causes the tiny blood vessels to spasm/diminish blood flow and delays healing. I have an ENT surgeon friend who wouldn't accept any patient who would not stop smoking, since their complication rate was much higher & they wouldn't behave after surgery. If you are okay with a bad outcome or delays in healing, go ahead.