Is it normal to have a bump on incision 3 weeks after abdominal surgery? (photo)

I had surgery because I got stabbed near the liver.however the bump I'm concerned about is above my belly button right on the incision.last week I went for a followup and dr.said it was build up fluid and she popped it witha needle.next day I had more fluid, I left it alone til it drain on its own but now the bump is hard and purple? Is that normal.please cause I'm concerned and my next appt is until the 6th There's no pain its jus like a hard jelly bean shaped bump no drain.will it be scarred?