Why does Jack's personality change when he applies the colored clay to his face in Lord of the Flies?

Jack symbolizes the animalistic tendencies found in the human condition. This is first shown when jack focuses intently on getting meat. He is consumed by primal urges and pulls away from societal ideas. He applies the colored clay to his face to symbolize his reverting back to a more primal state. Over the course of the book he has continued to progress to this end and the clay just shows the final aspect of this stage.
Because he uses the clay as a mask to cover up his responsibility to morality and therefore allows him to commit dreadful deads allowing his inner savage to come to surface