Hay I had some for years and being a girl they really bothered me but guess what spent all of last summer in the sun and I came back with a beautiful clear, shiny tanned back. If you can't go on holiday and are not ridiculously pale ( you prob have melanin in your skin if you've colour scarred) I'd get on a sunbed. I know your a bloke and all the cancer risk stuff but I would put 500 pounds on your back clearing up with enough sessions.
Cocoa butter doesn't really give results in my experience at least. Due to its greasy texture I wouldn't want to put it on my back anyway. It's drying out skin instead which makes it flake off and expose new layers which you want to do.