Amaranta wears a black bandage around her hand for her whole life. What does it represent? Actually, the bandage's symbolism changes throughout Amaranta's life.
She first puts it on after she drives Pietro Crespi to suicide and burns her hand on the stove as penance. So at first, the bandage seems to stand for her remorse about her actions.
But as she continues through life, never taking it off, the bandage starts to become a kind of misplaced armband – you know, the kind members of political youth movements strap on to show how committed they are to some cause. In her case, it's a commitment to virginity and obstinacy in the face of Colonel Gerineldo Márquez trying to date her.