The House of Mystery #192 1951

Image of Darkness" A deformed man finds a mirror which transforms him into someone handsome and places him in another world, but at midnight he reverts to his ugly self. He meets a girl, and they fall in love but she thinks he is standing her up for another woman after midnight and she breaks the mirror in a rage. He tells her the truth, and when midnight tolls, he becomes ugly once more and is pulled back through the broken mirror to the world he came from. The woman pleads with him not to go because she doesn't care what he looks like. He was beautiful on the inside.