In chapter 6 of "Lord of the Flies," why didn't Ralph feel pain when he struck the skin off his knuckles?

This occurs in the last few lines of chapter six. The boys have been scouring the island, searching for the beast. When they arrive at the part of the island that has not been explored and find that the beast is not there, they become excited and lose sight of what is important. As the boys are exploring, Ralph becomes anxious because there is not a signal fire, worrying that if a ship passes they will once again lose a chance of being rescued. When Ralph tries to get the boys to focus on the duty at hand, finding the beast so they can relight the fire, they complain and say they want to stay and play. Ralph becomes so infuriated at their lack of concern for rescue that he strikes the rock with his knuckles. He does this in frustration and anger, and he doesn’t seem to feel the pain because he is so overcome with the urgency to make the other boys understand the dire circumstances they are under. He is aggravated that he has to keep reminding the boys that the fire is detrimental to their rescue and that no one seems to really care.