to push up (one's hair) with one's fingers; to comb up; to smooth back (a wisp of hair)
彼女は前髪を手で掻き上げた。
She pushed her fringe back with her hand.
風で乱れた髪を何度も掻き上げている。
She is repeatedly pushing back her wind-tousled hair.
汗をかいた額の前髪を掻き上げる癖がある。
I have a habit of pushing back the fringe on my sweaty forehead.