If your overall weight is lower than normal according to your height , then that could be one reason for cheeks being not fuller.
there cannot be pore free skin, but your problem must be open pores & oily skin. Sometimes mental stress can lead to hyperactivity of sebaceous glands in the skin, causing open pores
Washing your face frequently with ice cold water & Application of rose water can close the pores, giving smooth skin.
some facial exercises can help change facial contour