what happens to the boy with the birthmark in chapter 2 in lord of the flies

The little boy with the birthmark goes missing after running away with the other children. He never reappears and is assumed to have died in the fire.

"That little 'un--" gasped Piggy--"him with the mark on his face, I don't see him.

Where is he now?"

The crowd was as silent as death.

"Him that talked about the snakes. He was down there--" A tree exploded in the fire like a bomb. Tall swathes of creepers rose for a moment into view, agonized, and went down again. The little boys screamed at them.

"Snakes! Snakes! Look at the snakes!"

In the west, and unheeded, the sun lay only an inch or two above the sea. Their faces were lit redly from beneath. Piggy fell against a rock and clutched it with both hands.

"That little 'un that had a mark on his face--where is--he now? I tell you I don't see him."

The boys looked at each other fearfully, unbelieving.

"--where is he now?"

Ralph muttered the reply as if in shame. "Perhaps he went back to the, the--" Beneath them, on the unfriendly side of the mountain, the drum-roll continued.