I'm Whitey McWhitebread. When I first met my tattoo artist I think he got a little bit of a tattoo woody looking at all that pale skin. I don't think skin tone has anything to do with why it faded. If anything, very pale skin makes the color stand out even more.
I'd leave it as is, but if you must monkey with it, make sure you get someone really good. They aren't going to "touch it up" they'll likely wind up going over the entire tattoo. If you don't get someone really good you have a better chance of making it look worse than making it look better.