It is the pain, it is the pain endures.
Your chemic beauty burned my muscles through.
Poise of my hands reminded me of yours.
What later purge from this deep toxin cures?
[Refrain 1] The way this line is repeated mimics a throbbing pain, coming in and out of focus. Just like the throbbing follows a rhythm, this refrain is expected to show up where it does. 

Villanelle It is the pain...