The girls are discussing whether the temporary teacher will remember their face, and then:
「どうかなァ...」 (the ellipsis is as written in the book)
"How about my name?"
"How about ..."
muttered Tama, and put her hand to her cheek.
This is not the first time I've seen ほおに手をやる and I'm not sure what to make of it.
How should I translate やる?
What significance does this action have?
I get the impression that it might be an action you make while you are thinking deeply. Is this a cultural thing or just a trait of this character? Or something else entirely?