“Acne dark spot?”

The use of that very potent cream should be under a dermatogist's supervision. However, generally speaking, if applied only to the brown spot, it is usually OK. Applied to acne acne sites or if those get contaminated with the product, the acne may flare up.

That is a good combination for hyperpigmentation, and should work well for hyperpigmented acne scarring. A couple of thoughts, though. 1) fluocinolone is a steroid and long-term use can cause acne lesions, so only apply it to the spot, and not to the whole area. Of course, tretinoin is good for acne, so you don't have to be as meticulous with that one. It's usually a compounded mixture, so make sure you are only treating the dark spots, because, 2) It can lighten surrounding skin, even faster than the dark spot lightens. 3) I find that hydroquinone should be at least 4% to be effective, so if you are having it compounded, ask for the 4%.

Usually, dark spots caused by acne are post-inflammatory hyperpigmentation and will fade gradually over time. I would recommend daily SPF 30+ as well as other non-steroid/hydroquinone based preparations or chemical peels to help improve the appearance of the skin.