Feeling, somehow, very nervous, he drew the mirror closer to him, lest he should fit the nose awry. His hands were trembling as gently, very carefully he lifted the nose in place. But, oh, horrors, it would not remain in place! He held it to his lips, warmed it with his breath, and again lifted it to the patch between his cheeks—only to find, as before, that it would not retain its position.
"Come, come, fool!" said he. "Stop where you are, I tell you."
But the nose, obstinately wooden, fell upon the table with a strange sound as of a cork, whilst the Major's face became convulsed.
"Surely it is not too large now?" he reflected in terror. Yet as often as he raised it towards its proper position the new attempt proved as vain as the last. (2.117-122)
The nose has been out in the world and it's gotten too fancy for Kovalev. Or something. Basically isn't this just a way over-heightened version of that weird feeling you get when you try to put on clothes that are too cool or too whatever—just not quite right for you somehow? It's like your body isn't really just your body but an extension of your personality. And what if they don't match? Then bye-bye cool new version of yourself.