How to sleep after septoplasty? Also do I wake up to change gauze in the middle of the night?

Typically, the first week after a septoplasty is not a fun one. I generally recommend sleeping with your head elevated, either with several pillows or in a recliner. Don't expect a full night's sleep. Frequent naps are more likely. I would only worry about rinsing the nose and changing the gauze when you're awake, but check with your surgeon. Everyone has their own preferences when it comes to postop care. Happy healing!