Congratulations on quitting smoking - that's the first and cheapest step to a more youthful appearance and better skin.
It can be difficult to give suggestions to you based on pictures without a complete clinical evaluation in person. The previous replies by all the doctors have lots of valuable information within and have touched on the various non-surgical treatments available for you, notably for skin firming/lifting purposes.
My personal opinion is that it depends on the look you are trying to achieve on your face. Fat is important on the face, but equally important is the amount of fat, and where this fat is located.
As Asians, we often have broad, underprojected faces with a heavy lower face and a short chin. As we age, we will experience volume loss of fat, muscle and bone, and consequently also experience descent of the skin or sagging due to deflation.
Whilst, fat preservation in certain areas of the face is crucial to reduce the effects of this, it is also difficult to expect someone to live with a round, chubby face in anticipation of this. Therefore, it is vital to have a detailed consultation with someone experienced in this, prior to embarking on any surgery to the face.
To answer your question on the surgical options (as the non-surgical ones have already been expounded on), the treatment of the heavy, saggy, chubby lower face are - limited buccal fat removal combined with a skin firming/lifting procedure, and facial liposuction.
The choice of either depends again on the clinical assessment of your face in person and the look you are trying to achieve.
Best Regards
Dr Samuel Ho