This is the 10300th most frequent Japanese word.
顔面
Face; facial surface.
Here, 顔面 refers to the entire face as an expressive object, indicating emotions visually on the face.
彼の顔面に驚きを浮かべていた。
His face showed surprise.
In this case, 顔面 is used to refer to the physical part of the face that was impacted.
顔面を強く打たれてしまった。
He was struck hard on the face.
Here, 顔面 describes the surface of the face which needs protection, emphasizing its functional aspect.