Having a seroma that far out of surgery is not unheard of and is more common if there is a foreign body such as a mesh there. It is important that that fluid be sent off for any abnormalities such as infection and/or abnormal cells (At least in my opinion).
Edema after a tummy tuck takes about four months to resolve completely and you won't know if the upper area is dented or just not edema maiden like your lower abdomen. If is still there after full recover and healing from your tummy tuck it can easily be fat grafted!
