Someone has said something to the speaker, and the words stick in their ears, though they can't tell what is real. All they have are whispers, rumors, and things left unsaid. The poem pictures these as knives thrown into darkness: nobody sees where they land, but they still wound, and they blur the line between what happened and what was imagined.
The middle of the poem turns to the idea of a deeper truth. It sits behind the lips and in steady eyes, and it "burns only when touched." That image suggests the speaker is afraid of getting too close to the truth, whether it's someone else's or their own. So they hide.
The ending is the most telling part. The speaker is surrounded by "devastation" and says "I don't want to hide," right after saying they do. The mood is anxious and torn, caught between protecting yourself and wanting to step out and face things.