Most patients continue to have the implant settle and overlying tissue remodel for a year after augmentation. You have more asymmetry than typical for being this far out. Your right breast may have developed a contracture. It is unlikely anything was done "wrong" during your surgery. Asymmetry and contractures sometimes happen following augmentation, even when everything is done perfectly in the operating room. Follow-up with your surgeon she he/she can determine what is going on and what the best course of action is.