Which Workouts to Lose Excess Skin?

So I've loss a total of around 60lbs in about a year. I just recently got back into exercising (I'm on my 4th week of regular exercise [4-7days a week]) after stabilizing my weight around 160lbs (this was mostly through diet, though I had a month of non-stop exercise in the middle of this).

My main concern is that even with exercising, I can seen I've gain muscle, but the pesky stomach skin is bothering me (more than the old stretch marks or the arm skin). I know its skin and not fat (at least mostly), since I can move it to see a flat stomach and when I lay down, its sinks in (see picture)

Is there a workout regime I could do to loss some of the appearance of excess skin?