Undermining overstatement

Eli, on his ride with the Indians who steal him and his brother says:

I doubted there was any skin left anywhere below my waist.

and

There was nothing to protect us from the sun and by afternoon I could smell my own burning skin.

I imagine there was skin left on his thighs. I imagine he did not smell the charred meat of his shoulders. Does he overstate because he is a child still? Is this over-emphasis characterisation? Or is it clumsiness? Obviously the journey is arduous and the author needs to convey this, but I found both sentances jarring and ill-judged.

With questions about the author's judgement I was puzzled by Martin's conversation before his death. He had seen his mother raped and murdered, his sister raped, mutilated, and murdered. Yet he talks with calm about the letters he had written to Emerson; how the Spartan's were "cockchafers"; he wonders aloud about the destiny of flowers denominated Mexican something vs the flowers denominated Indian other. He blubbers and shits himself but he refuses water and in the end he doesn't drop to the ground when speared. I didn't feel I was reading a multi-facted character with hidden strengthes, I felt I was reading an inconsistent portrayal, a tool to allow the author to expound on other matters. I was not in the least convinced by either Eli's or Martin's reactions to their capture. But I hope Eli's character in later chapters will redeem this portrayal, and I'll do my best to reserve judgement.