nose whistle

Hayden shed badly yesterday. During his nice soak, he kept propping his head onto the side of the tub and making a loud whistle. He's never made this noise before. Do you think it's maybe because of retained shed in his nose? Would another soak be in order?

If the rest of the shed is off with that one soaking, then I wouldn't worry about it. If there's a bit stuck in his nose, it'll likely clear out on its own soon.