A deviated septum affects your nose by making one nostril narrower than the other. This can lead to several complications. If your deviation is bad enough, it could block one of your nostrils altogether and hinder drainage from your sinuses. This can cause chronic sinus infections. Constricted airflow may also dry out your nasal cavity and increase your risk for nosebleeds. On the other hand, if you only have a slight deviation you may not notice it all.