Pigmanorm cream for 8 months didn't work for my melasma. Now, my doctor wants me to try hydroquinone 4% cream. Can this work?

I used pigmanorm for 8 months, but I wasn't very diligent about sun protection. So, I never wore hat or tried to cover myself, just used the sunscreen once in the morning.I also didn't used any exfoliation scrubs etc either.My melasma was induced due to using obagi nuderm for small acne spots and going out in sun without sunscreen plus use of birth control pills. Does hydroquinone work for everyone? why wouldn't it work for me? how can i make it work for me?