No, there is no exercise to add fat to your cheeks (adipose is the medical description of this fat that gives our faces definition). Your body distributes fat proportionally, according to your genetic makeup and predisposition. Some people gain it in specific areas of the body naturally; women generally tend to add fat to hips, thighs and buttocks. Short of cosmetic procedures, or gaining weight again, your cheeks will remain proportional.
As far as improving your complexion, a balanced diet, with plenty of fruits and veggies, plus regular exercise will help provide the nutrients and circulation your skin needs to be healthy. Steer clear of caffeine, tobacco, alcohol and other drugs, and limit your intake of refined sugar and processed foods/simple carbs. Zuhail has also made a good point about doing your best to limit or manage the stress in your life, because stress hormones can affect health overall.
As far as improving your complexion, a balanced diet, with plenty of fruits and veggies, plus regular exercise will help provide the nutrients and circulation your skin needs to be healthy. Steer clear of caffeine, tobacco, alcohol and other drugs, and limit your intake of refined sugar and processed foods/simple carbs. Zuhail has also made a good point about doing your best to limit or manage the stress in your life, because stress hormones can affect health overall.