The above edit was done using RawTherapee, nothing else! RawTherapee only has a very basic spot removal tool, which made this a nice challenge 
I used that to get rid of some of the skin irritations/blemishes and I used a few Local Adjustments instances to deal with some of the other issues.
I normally have a different workflow that starts with RawTherapee and, often times, ends with Krita. Even though darktable has a rather nice set of retouching tools I still think that software like GIMP, Krita or Photoshop, to name just these three, are better suited to do serious retouching.
What I normally do in Krita? This is an old topic of mine, from over a year ago when I started using Krita: Krita: A worthy image retouching and compositing editor? It mentions some of the things I do. Not much different from what one would do in GIMP or PS. I feel a lot more comfortable using Krita nowadays, Iām certainly more proficient and learned some stuff. The exact workflow depends on the image and its often unique challenges.