Will I be able to naturally regain volume in the cheeks if I quit smoking?

Unfortunately, quitting smoking will not reverse
the negative affects that have already presented themselves such as premature
facial aging. Cutting tobacco out of your life will, however, slow down the
accelerated process of aging that a smoker experiences. There are other means,
such as injectable fillers, that can help restore lost facial volume and can
improve your self-image as you get on track toward a healthier lifestyle. Consult
with qualified doctor near you to assess your condition and to determine what
approach will work best for you. 

Stopping smoking would help overall. It may not restore volume to your face but rather get you on track of a normal aging process.