I have flatness at mid face. Is it a massater or maxilar problem. Why? (Photo)

Flatness in the mid face can be helped with Juvederm Voluma XC injections.  This would be on-label treatments.  You could also do off-label injections with Voluma to your jawline and chin to help with symmetry and enhance masculinization.  With fillers it is important to be conservative to maintain a natural appearance. Good Luck.   

you are a good looking guy, and if you want to look more masculine filler placed in the right locations (mid cheek, jawline, mandible) would do very well to give you a subtle masculinization.  otherwise, you look normal for your age.  I would not suggest mandibuilar botox as that can round your face which would not look attractive on you.  I would suggesting increasing the size of your masseter area by using fillers.  If you are considering anything, go to someone very well trained in treating men.  Best, Dr. Emer.

I believe you would benefit simply from some fillers to give your face more angularity.  Angularity is a very  masculine trait (Brad Pitt)!  Adding the appropriate filler to the appropriate area gives a great result!  See the link below for an easy 10 minute treatment.