This is my expertise and a huge portion of my practice. Asymmetry is normal and expected. Buccal fat pad gives slimming not symmetry. Masseter botox will make you slimmer and make the jawline more loose. Fillers help give shaping and contouring. If you want perfect or close to perfect symmetry...
We typically all lose volume in our face as we age.Smoking can be very harmful, can age you faster and cause wrinkles but typically does not make you lose volume.Fillers like Voluma are very natural and can last up to 2 years or more and are reversible if needed.
Please post a picture to best see what your referring to. Cheek reductions can be done, but to better help you please contact a double board certified plastic surgeon for a consultation to discuss how he or she can best help you reach your goal and to get a full evaluation.