I'm sorry to say but you will not be able to fix this and make it look like it never happened- the only way to do that is to re-shoot. however, this is what I would try:
Create a animated mask on a white solid that follows the banding- theoretically this should be constant, so you will need to create a loop- animate 2-3 such masks to be able to create that loop (not seeing the footage makes it impossible to tell exactly how many masks you need to animate and what feathering they should have). Put a black solid under and render out the loop. This is your matte. Composite the clip on top of itself using this matte and color correct to match the banding - probably you will need to apply color correction on both layers to bring them in some what of a visual harmony. It may work or it may not< but it seems to me in your situation that it may be worth a try.