Self esteem maintenance is controling your self esteem. Like whenever you get up in the morning and look in the mirror, if you don't like what you see, change what you see. Don't be too critical on yourself.
The mirror symbolizes how he doesnt want to see his inner self. Society has told us that if we dont look a certain way then were ugly. He felt ugly so instead of looking in the mirror and being haunted with his "ugliness" everyday he covers them so he doesnt have to see himself.