Collagen after breast augmentation, increase in scar tissue?

I know of no data that shows increased intake of dietary collagen will cause excessive scar tissue formation after augmentation or any other surgery. A number of factors can contribute to excessive scar tissue formation, including mechanical and thermal trauma at the incision site, tension on the wound, and reaction to suture material. Genetic predisposition to excessive scar formation, as in patients who routinely form keloids, can be a factor. 

There is no one best therapy for scars. Silicone sheets, Mederma, and Biocorneum are reasonable and popular options. I recommend that the scar therapy begin after the scars have healed and there are no open areas, which usually takes 4 to 6 weeks. Ask the PS who performed your BAM about taking collagen.
Kenneth Hughes, MD, ABPS Board Certified Plastic Surgeon
Los Angeles, CA

I do not believe there is any scientific evidence that collagen supplementation leads to excessive scar formation. Standard scar-decreasing maneuvers such as relief of tension, sun-avoidance, massage & perhaps silicone (usually reserved for when/if scar hypertrophy actually forms) will be helpful.
Best of luck & enjoy your results!