The main character is a man. He lands on an alien planet and cannot leave. He lives with the natives for a long time. Near the end of the book a spaceship lands on the planet and he describes the aliens that come off of the ship. We later learn that they are actually humans but he has been living with the natives of the planet so long that he has begun to see things from their viewpoint and has forgotten what he actually looks like to them. He sees the humans and they look strange to him. I remember when he describes the humans he talks about how fleshy or puffy they look. I'm not positive but I think the natives he's been living with are ghost-like.
Does any of this ring a bell with anyone?