I would edit this image in two steps.
1. Edit the overall image to get the dress looking like you want to.
2. Edit the skin for a deeper tan:
Using the adjustment brush, turn on the auto-mask, select the arms and chest.
Make the brush very large, select a few of the holes showing the skin.
Now that you have all the skin selected adjust the color for the tan. I tried something like:
You will need to play with the settings as it is easy to go too far so that the tan looks fake.
Keep in mind that one of the reasons the bikini woman looks so dark is that she is backlighted, which places her front in the shadows to start with. The white clothing exaggerates the effect much more than the dark dress does.
If you have an image where you can globally change one color, then the HSL panel is very useful.
In your image skintone (yellow/orange) is 'global' and can easily be darkened by selecting [Luminance], clicking on the 'Targeted Adjustment Tool', and dragging the luminance of the skintone down with the mouse.
It may not always do the job but worth trying.
thank you so much, I will try that!
Thank you so much, this looks like it might be it, will definitely be trying this method!
Thank you, will look into it