Breast reduction wound has split open and keeps splitting more. How do I stop the incision from opening more? (photos)

Hi and welcome to our forum!
The operative procedure of breast reduction involves
separation of the skin and soft tissues of the breast from underlying breast
tissue followed by removal of excess skin and breast tissue. The skin and soft tissue is then advanced downward and the excess skin
and soft tissue is removed in an inverted "T" fashion.  
If the closure is tight, if there is blood supply impairment or if there is failure of the suture line, the wound will separate (dehisce). No skin or soft tissue is lost. Wound separation prevents the buildup of underlying pressure which could otherwise jeopardize tissue survival. Blood supply impairment can be due to the effects of smoking, diabetes mellitus, vascular disease, previous surgery in the area (disrupting the normal blood supply), infection, or may totally inapparent.   As swelling decreases, the wound will begin to shrink and eventually close. Frequent local wound management is required. Wounds of this size will usually seal within 2-3 months under direction of your plastic surgeon. 
I am often surprised how well these scars often heal.
Best wishes...