Necrosis of Belly Button, 2 Weeks Postoperative from a Tummy Tuck. What To Do?

I am 2 weeks post op from a tummy tuck. Over half of my belly button has become necrotic. It has gone from black and hard to now brown and white ish in color. It smells and is red around the opening. My plastic surgeon says it will slough off and be normal. Is this true and how long until it is normal? Should I be putting anything on it? Can a surgical procedure fix it and should one be done? Thank you!