I would just let it be and let it figure things out on its own. If it's unhappy, it'll certainly move and find a place to hide. Nems generally like to hide and bury their foot in nooks and crannies in rocks. If you can give it that while it still get some ambient light (not being blasted by it), it may be able to recover.
I recently got a couple nems from MACNA and one turned completely white. However, it looks rather healthy as its foot is firmly attached to my rock and bubbles up. It's only starting to color back up again so there's definitely some hope. In the process of mine bleaching, I left it entirely alone (minus the clowns rubbing incessantly in it).