When it comes to editing skin tones, Adobe Photoshop has always reigned supreme. Lightroom could change the white balance and even alter the Hue, Saturation and Luminance values, but this is often not accurate enough to render great skin tones.
This changed with the introduction of RGB curves in Lightroom 4, allowing us to change the values of Red, Green & Blue at a specific tonal range of the image. How this changes things will be explained below, but suffice to say it makes for much nicer skin tones without the need to export to photoshop. [More]