Oh boy, a lot going wrong in these pics! If nothing else this is a great example of why you need to get your pics right in camera, even if a lot of PP and retouching is going to happen afterwards.
I don't really think the first one is worth bothering with given how bad it is and how hard the light is. Looks like everyone else is of the same opinion thus far, given people have only attempted the second pic.
Thought I would attempt this as I have never tried a full body major over haul before. Making this shot in particular tricky to edit, is her pose. The gentle twist she has between her hips and shoulders makes 'rendering' her new tummy difficult, combined with the fact that her stomach doesn't need a gentle nudge but a complete 'wipe-out'. Frankly I haven't got the skills (or the time today) to make it as good as new.
Anyway to my edit:-
- Curves used for colour correction, there was a stack of green light being reflected of that foliage.
- Spot Healing Brush, Healing Brush and Clone tool to remove major marks, blemishes and folds from skin.
- Liquify! Nudged that tummy a long ways.. slight nudge on the right arm.
- Brush tool, a lot of painting in skin tones to fix up the distorted weird looking stomach. More time could of been spent here.
- High pass sharpen
For a re-shoot with this model I would be thinking of getting her sent of to a make up artist before hand, I would also be looking to avoid the bikini shots. I'm sure she could look quite attractive in the right clothing, and it will be a hell of lot easier to make her a bit slimmer. Skin is tricky to deal with!
If you do have to go for the bikini shots I'd try experimenting with a lot of different poses, with the aim of 1). trying to make her look slimmer and 2). be able to retouch with as little effort as possible, to make her look slimmer.
And soft light! Please soft light.
Best of luck.