"Smooth face" is the most appropriate way to describe a face that is smooth in Engpsh. This phrase comes from the adjective "smooth," which means having a surface that is free from roughness, bumps, or indentations.

Here are some example sentences using the phrase "smooth face":

She appped a face mask and then ran a smooth stone over her smooth face to help with circulation. (她涂了一层面膜，然后用一块光滑的石头在她光滑的脸上按摩以帮助血液循环。)

He had a smooth face, with not a wrinkle or blemish in sight. (他的脸很光滑，看不出有皱纹或瑕疵。)

The baby's smooth face was completely free of any marks or imperfections. (婴儿的脸完全没有任何痕迹或瑕疵。)