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I believe that I read this in the early 2010s when I was in New Jersey, although I might have read it as far back as the early 2000s when I was in Ohio (I remember checking it out from the library and reading it in my apartment, but I don't have a firm memory of the location). A female researcher is stranded on an alien planet, specifically in a jungle that's incredibly deadly due to environmental poisons and dangerous beasts. The local sapient aliens take pity on her and turn her into one of them. The aliens are quadrupedal with long tails, I think more like cats or lizards than monkeys. Their skin changes colors, I think both for camouflage and to express emotions. Eventually, other humans return to find her, and she's confronted with the question of whether she can become human again, and if she even wants to.
It was a B-format or Trade paperback, primarily white in color. I remember that the cover was almost garishly colorful, all primary colors, I think depicting the jungle itself. I think the title was four words, in the form of "The X of Y". For some reason, "The Color of Passion" comes to mind, but searching on that doesn't get me anything useful.