Will a hydroquinone-based product like Scarguard Lightener permanently & safely lighten a neonatal circumcision scar? (Photo)

When I was circumcised as a baby, the resulting scar was very dark and uneven. It has always embarrassed & bothered me, and I've gotten negative comments on it from women. I want it gone. I read hydroquinone can lighten "dark brown scars" which sounds like what I have from a nenonatal circumcision. The OTC Scarguard Scarlight / Lightener says to ask a DR if applying to a mucous membrane (where part of the scar goes). Will it work? Permanently? What are the risks that prompted the warning?