i think in my very inexperienced mind the next step is quiete, dark, lots of towells, and mix feed and water with a sugar cube into a little sweet warm porage and wait the night out.
Warm sweet porage braught a few of my birds back to life
Were all hoping for you, Poor duckys come so far already
X2!
Did you take your eyes off him at all? Looks like the aftermath of a smack on the head
edit- I realize how stupid that question sounds. acting like a bump on the knoggin but iam often and usualy wrong. Untill some splid advice comes ide do what @Miss Lydia seid and softly restrain