I am submitting this paragraph today (it's part of a story), and I was hoping someone could check its punctuation and tell me if it's correct or not?
Thanks in advance!

The straps they used seemed to be hard edged, pressing into his flesh as though growing tighter; a serpent’s length winding around its unsuspecting victim. Edward’s skin had purpled from the pressure this caused, and his entire body lay vulnerable – birdlike and slight. He struggled to open his eyes, and when his surroundings finally fell into focus, they were met by a clinical, white room. After tilting his head to the side, he suddenly noticed a rat scuttle into a crack in the wall, its long, thin tail dragging through a dark puddle on the floor. The pain caused by the straps had awakened his senses, and he was overwhelmed by panic – he prayed that he was lost in a nightmare, simply awaiting release.