Does tret treat hyperpigmentation/melasma?

I have a pretty big patch of melasma on my forehead and I’ve had it for 2.5 years. Really annoys me. I’ve been using 0.025% tret for a while, plus mandelic acid but haven’t really seen a difference. I am now living in a very hot, humid country where apparently hydroquinone is banned? Not sure why. Do I have any other options?? I’m worried it’s going to get worse and spread to my cheeks…