Scar treatment should in general start sooner rather than later
If you had a plastic surgeon perform your breast augmentation properly, the incision should be small and well hidden. It sounds like he/she wants you to allow the incision to heal before trying to manipulate the appearance of it. This is because it takes the body approximately 6 weeks to achieve peak strength in terms of scar/collagen formation.
If your scar is becoming hypertrophic or wide there are many treatments available but few are typically successful. At this...