5 week since breast reduction and I have a slight split! What do I do

These type of superficial incision line separations and/or wound healing problems are not uncommon after breast reduction/lifting surgery. These areas generally go on to heal without long-term sequelae. Best to follow your own plastic surgeon's  recommendations as opposed to online consultants who do not know your precise situation and who are not responsible for your care.

 Best wishes;  hopefully you will be very pleased with the long-term outcome of the procedure performed.

This is not an uncommon occurrence after breast reduction surgery.  I would consult your plastic surgeon as far was what he/she wants you to do with dressing changes.  I usually recommend to my patients silvadene cream to the area and cover it.  Change the dressing once a daily and wash the area completely in the shower.  The area generally heals with out much issues.  I also advise my patients to wear a good support bra to help take the tension of the incisions.  Hope that helps.

I assume that your plastic surgeon provided you with wound care instructions based on your described regimen of care. Generally, wounds tend to heal better somewhat damp vs completely dry. Regardless, your wounds will heal in time. If you are still unclear about your wound care, please call your plastic surgeon's office to make sure you are following their guidelines correctly. Thank you for sharing your photo and concerns. Best wishes.