What is this discoloration? Bruising or something else? (photos)

Dear dominicanprincess19,
I understand your concern. However, without a proper assessment, it would be difficult to determine what went wrong. It is best that you visit your plastic surgeon for further assessment or ask for a second opinion. Only after a thorough examination, you can get proper recommendations and advice.
Daniel Barrett, MD
Certified, American Board of Plastic Surgery
Member, American Society of Plastic Surgery
Member, American Society of Aesthetic Plastic Surgery

Hi and welcome to our forum!
From your photo, I note well healed inframammary scars (below the breasts) but broad hyperpigmented vertical and periareolar (around the areola) scars as well as an apparent notch deformity at the bottom of the left breast, suggesting the presence of excessive tension at the original closure or a healing delay after surgery. There are non-surgical modalities available to lessen the appearance of the scar (such as laser, skin bleaching, etc.) A moderate degree of success may be noted after treatment.
If a year has passed since your breast reduction (to allow for subsidence of swelling and the hypervascularity of healing), you may wish to consider revisional surgery. 15% 0f cosmetic surgeries can be improved through secondary revision.
Revisit your plastic surgeon for evaluation and discussion.
Best wishes...