Will the skin smooth out after tummy tuck? (Photo)

At 4 weeks you are still far from healed although you are likely feeling better. The appearance you describe is pretty typical and usually will smooth out with no problems. It's at least 12 weeks before you can truly judge your result.

Allow 6 months, sometimes up to 12 for all the swelling to resolve. I would expect this small amount of irregular contour to resolve as healing progresses.  If I am wrong, the fix is a simple office procedure.All the best.