The body we see is an illusion created by the mind. Our eyes take in external pictures of the world which our mind interprets as reality. When we look at our own body, we are only seeing a mental picture created by memorization of the front view. We cannot see or remember what our back looks like because it is not in our memory. Through meditation, we can come to realize that the body is just a mental construct and does not truly exist as we perceive it. We should not worry so much about something that is ultimately invisible.