This time his hair actually turns black, and his eyes turn blue, and he opens his mouth - 

winces, realigns his jawbone with an uncomfortable crunching sound - 

- and says, "I owe you several apologies, I think." 

Meanwhile:

Basically everyone in the year who's not scheduled to be in Astronomy right now (Carter, Gadlen, the Vector twins) and doesn't have a free study period instead (Bones, Snape, Wilkes, a few others) is supposed to be in Charms. They're usually not scheduled on top of each other, but this year there's no overlap and the next best physically possible overall schedule was in all other respects worse. 

A weird number of them aren't, though: Evans, who definitely signed up for Charms and is nowhere to be found; Kovachev, who is apparently having some kind of medical problem; and Hall, who apparently was last seen making unhinged Slytherin-related choices for no discernable reason. The second two things might be related, since they're roommates, but it's sort of hard to see how.

"Good morning, good morning! This is NEWT Charms and I am so delighted to welcome all of y--" 

Flitwick stops. He leans forward from his perch on his desk, squinting. He consults his classlist. He puts on his spectacles, just to be quite sure. 

"--some... of you?" he corrects, worriedly. 

"Uh, Sasha's in bed with a migraine but he's not like dead or anything," volunteers the remaining Hufflepuff in the room, Dáithí Moran. "Daniel's probably on a friendship quest?" 

This is a common Hufflepuff phrase meaning actively engaged in trying to rescue someone from evil by the power of friendship, a thing they do all the time. 

"Lily is um. On a non friendship quest. I think." 

Did he miss her explaining this while his brain was full of exclamation points? Heck. Immediately failing at being the best boyfriend ever. Gotta work on that.