I have accessory breast tissue I need to have removed. Lymph node risk?

While there probably won't be any lymph node interference during surgery, it is best to schedule a consultation with your plastic surgeon to have an in-person examination and address your concerns.

should easily be removed without impacting your axillary nodes... as you are not having a node dissection.  All your surgeon should be attempting to do is to make the contours better... not removal every bit of accessory tissue present, unless you want the tissue all gone.