There are many ways to fix a septum. Generally cautery is used only on the turbinates or the initial incision on the columella in open techniques. The septum is like a wall frame in a house. The skin (mucosa) over it is like wall paper, and the cartilage on the inside is like drywall. You place an incision in the front part of the nose where it is hidden and raise the wallpaper off the wall. Then you can perform the necessary correction to the drywall (cartilage) and when you put the "wall paper" (mucosa/skin) back it looks like nothing was done.
Usually packing will be required however, some patients are eligible for tubes or straws placed in the center of the packing on each side so that direct airflow through the nose is possible. Most patients find this a psychological discomfort rather than a physical.