"A Beautiful Girl Combs Her Hair" certainly is filled with beautiful imagery. I could very easily picture the girl "standing on the ivory bed, loosening her hair, watching the mirror..." The poem also contains metaphors. The speaker refers to the girl as a "lotus blossum" and "a wild goose on the sand." I especially liked line 17, "drop the jade comb-no sound." Maybe this is where the translation differs, because it doesn't read "she dropped the jade comb" or even "drops the jade comb" with the subject understood. The image that I see, however, is a beautiful, heavy jade comb falling on a bed so fluffy, pillowy, and soft that the comb doesn't make a sound. The luxurious bed, the silk curtains, the cherry blossoms just down the steps, and the girl's long, thick, perfumed hair make me visualize a paradise as rich as the imagery itself.
It seems the speaker is the one who is "Awake at dawn" as the first line says. "The lotus blossom wakes" in line 8. Perhaps he woke early to go watch this girl whom he admires wake up. Or maybe he is so in love with her that he could not sleep for thinking of her. He was already "Awake at dawn" and couldn't stand being without her any longer so he had to go see her.