In these lines from Hanging Fire, we can observe personification and enjambment. Personification is observed when the author states "... and my skin has betrayed me". Personification happens when a writer gives human qualities to something that is not human (decision making kind of human). While skin is part of the human body, is not able to make decisions such as betraying someone.
Moreover, we can also observe enjambment because of the lining of the stanzas. The original text looks like this:
I am fourteen
and my skin has betrayed me
the boy I cannot live without
still sucks his thumb
in secret
Notice that the author changes from one line to the next without any punctuation end (periods, commas, question marks, etc.) and disregarding continuity of the idea.
Therefore, your best answer is personification and enjambment.
