We all know smoking is bad for your skin. It also has a detrimental effect on scars. In fact it slows the healing process of both wounds and scars. Scars are more likely to become wide, thick, and red.
To be more precise, by smoking you decrease the amount of oxygen in your blood. Apart from that, nicotine narrows blood vessels (capillaries) which decreases the blood flow to the skin. So a lower blood supply and less oxygen are the result.
Most surgeons refuse to have people undergo scar revision surgery. Not only because it’s far less effective when someone smokes but also because it complicates anesthesia, and increases the risk of infection
Especially in case of cosmetic surgery since it’s all about appearance. Most plastic surgeons require a patient to quit smoking for at least 2 weeks prior to surgery.
Other ways to improve scar healing after surgery (or in general) are to maintain a healthy diet with sufficient protein, a well balanced fluids intake keeps you from dehydrating, and avoid alcohol as much as possible.