A little more research that might come in useful

Hydroquinone (HQ) is one of the treatments that can be used for melasma, but the general consensus is that its a bit risky - it can cause inflammation in the short term, and it can cause rebound re-pigmentation, which is sometimes more severe than the original pigmentation. I was active on another forum, which I've referred to before, and I found that a lot of these women were paying hundreds upon hundreds of $$$ on these very harsh treatments, some containing HQ and some claiming not to. A number of women had no results after paying all that money, and a few suffered worse rebound darkening, and skin damage due to inflammation. I was puzzled that a product claiming to contain no HQ was causing HQ like rebound pigmentation, until I realised that the arbutin (a natural substance derived from plant sources) in these treatments actually converts into HQ on contact with alkaline conditions on the skin.
Just thought I'd post a link to the original thread - it's worth reading through the entire thread to see the questions and comments that ensue.
Some people were livid, both with me and with the manufacturers of these creams, they had spent tons of money on these treatments and had in most cases been told that they were having problems because they werent using them correctly.

http://skincarerx.com/phorum/read.php?3,7028,page=1

Maybe this will be of help to someone, maybe not

Mel Tweet