Lord of The Flies reveals the challenges of life without boundaries, in the absence of "grown ups" and, in Jack's case, the instinct to hunt despite maintaining that "we're not savages. We're English."]'
The boys are school boys, not yet affected by the stresses of adulthood and yet they will resort to savagery and will suffer the "loss of innocence."
Having lost the election to be made leader, Jack is consoled as he will get to lead the choir - or rather "the hunters." As time goes by Jack becomes more comfortable "steaming with sweat, streaked with brown earth"after his previous encounter with the pig he was unable to kill.
Jack paints his face, becomes obsessed with hunting and, devoting himself to his task, paints his face. This seems to release him from his responsibility of being the respectable choirboy - "chorester head" - that he actually is. The more savage Jack becomes, the more he is able to to control the rest of the group - his "tribe." As he gains more authority, Jack becomes more brutal. Fear is a powerful tool which Jack uses against the boys as he recognizes that he can control their behavior due to their fear of the "beast."
Hence, the change in Jack's appearance allows him to shrug off his civilized self, without any associated guilt. Furthermore, he can control the other boys as Ralph steadily loses his effectiveness.