Breast lift wound separation: should I have it re-stitched by a surgeon or try local wound care (vacuum) first? (Photos)

I am sorry to hear about the complication you have experienced.  You will find that there are many ways to treat these open wounds; there is not necessarily a "right answer".  Much will depend on your physical examination, your plastic surgeon's judgment/experience/preferences,  and your preferences.
 Generally speaking, these wounds go on to heal through a process of contraction where the tissues heal from the sides towards the center of the wound;  this process usually takes several weeks/month to occur, depending on the size of the wound.  Sometimes, depending on the size of the wound, a wound vac may be helpful.  Occasionally, removal of unhealthy tissue (debridement) and/or removal of exposed sutures, may expedite the healing process.  Generally, I would not recommend direct wound closure;  I think that the risk of infection and potential need for reopening the wound is significant.
 In my practice, I would likely recommend that you continue to exercise patience and allow the wound to heal by contraction or consider the use of a vac device.
Best wishes; hopefully, you will be very pleased with the longer-term outcome of the procedure performed.  Sometimes revisionary surgery (for example scar revision) as may be necessary to improve the outcome and/or breast symmetry.

You may have waited too late for reclosure and will need to continue with wound care until healed. Later, your surgeon can revise your scar should it be too wide.

Thanks so much for reaching out. At this point in time I would suggest continuing with local wound care. Do this until the wound is completely healed. You will likely have to wait 12 to 18 months have this area revised.I hope this helps :-)