I had a chemical peel done on my back not long ago that cleared up a lot of the marks left by breakouts, but it left what looks like a stain that is somewhat darker than my skin (I am a light-skinned African American). This was at a spa about 2 weeks ago, and there was no prep before-hand. I've heard that hydroquinone will help lighten it, but will it only be temporary and will return or even darken after I discontinue use. What can I do to make sure it doesn't return after it lightens?