Flat spot on the bottom of left breast? (Photo)

This may be related to normal asymmetry.  Fat grafting may help the area if it is a volume issue. Best to be evaluated in person.

That is a very good question. It is likely that the flatness you see is a result of preexisting asymmetry (different amount and distribution of breast tissue) of the 2 breasts. Although we associate the body with two equal sides, it is almost never seen in people when you examine them thoroughly. If you look at someone's face, you can almost always see a big side, a bigger eye, eyebrow differences, etc.. This occurs everywhere in the body when comparing side to side. One of my patients told me once that when it comes to breasts ",They are sisters, not twins." That being said, and kudos to your surgeon for telling you to wait because many of these issues go away with time, once you have an issue like this, the question is what to do about it? Revision rates in Cosmetic Plastic Surgery can be as high as 30+% in some studies and when I discuss this with patients I ask "how bad does this bother you?' If it is more than a 6 out of 10, we discuss options and what is involved. Fat injection to increase volume is one reasonable option, another is to decrease volume in the other breast (Liposuction). In your situation, adding volume appears the better choice. Discuss all of this with your surgeon. Overall, your result is quite good. Best of luck.