What does Dimmesdale tear off his clothing? The Scarlet Letter

Dimmesdale tears off his clothing to reveal his own mark of shame.

"With a convulsive motion he tore away the ministerial band from before his breast. It was revealed! But it were irreverent to describe that revelation. For an instant the gaze of the horror-stricken multitude was concentred on the ghastly miracle; while the minister stood with a flush of triumph in his face..."