Try Mexican/Flapscale Blenny, Paraclinus mexicanus/sini. Humann/Deloach Reef Fish Baja to Panama Page 189. They say it's impossible to tell the two species apart visually underwater.
Yes, that is the one. The color pattern in Reef Fish is far from what I saw but they apparently vary quite a bit. They did have the spot on the dorsal fin and the dark band below the eye.