i assume he felt it already, but you could ask him two questions.
tell him you've heard of a lot of guys being less than satisfied with lipo only and ask him how many excision cases he's done. you want him to have done this a lot in order to trust his call.
ask him if he would be willing to do excision in mid-op if he changes his mind on looking at it.
the armpit approach assumes lipo with no excision. it'll probably leave a lot more bruising, though that should heal over time, and be your only scar. o.t.o.h., a small incision on the edge of the areola may heal up fine in half a year to a year but still let him see more. so that depends on how the first two questions go.