What is going on after my breast reduction? It had a little infection which they cleaned out. (Photos)

Unfortunately you have developed a large area of skin necrosis and the wound is now granulating. With regular dressings this should heal and you will need advice re the dressing and subsequent scar management. This will take a number of months and best that your PS sees you regularly through this time. 

Dear nikelynn23,
this type of wound is not uncommon after breast reduction. It is usually caused by poor blood flow. I would suggest you to follow your surgeon's instructions and keep your wound clean and covered. It can take few weeks or months for wound to fully heal. 
Daniel Barrett, MD, MHA, MS 
Certified, American Board of Plastic Surgery  
Member, Am. Society of Plastic Surgery

Hi and welcome to our forum!
Breast reduction requires extensive undermining of the tissues, partially stripping away the blood supply. Although the incisions are designed to minimize this phenomenon, partial skin loss is not uncommon. The underlying tissues are granulating ( developing a beefy red complex of blood vessels which fight infection) as there appears to be adequate soft tissue blood supply. Once the granulations mature, the wounds will begin to shrink over 6-12 weeks, sealing the wound from the periphery inward to the center. In most instances, these wounds will completely seal. On occasion, a skin graft may be required to completely seal the wound. A regimen of intensive wound care will be required. Close followup with your plastic surgeon is necessary.
Allow the scars to mature over 12 months. Many patients do not require scar revision!
Best wishes!