Some parts of body we cannot see

My nose is little bit big. 

Whenever I see my face in mirror, I find it lacks a curve which is between the front a small big size and latter on a narrow long part of the nose. 

Whenever I focus my one eye on my nose directly without using mirror, I can see the front big size and small part of the long part of the nose. 

But normally my eye fails to see it very focused as I can see the objects which are few centimeters from eye. 

If I use my both eye, I am unable to see my nose. 

I am thinking which other parts of my own body I cannot see if I do not use any other tools which can make the image such as mirror, camera, water, light reflection etc. 

What do you think? 

Which parts of your own body, you cannot see?