Adobe Photoshop & the power of camera RAW have brought about possibilities that never existed before.
In the days of old, you were limited to what you can achieve with retouch / photo enhancement. But now, with powerful tools existing within Photoshop, it is all made available; nothing is impossible as long as you possess enough knowledge & are willing to put in a decent amount of effort into post processing.
Now what I'm about to share today is not something I'd recommend, nor something I'm very much proud of sharing as a photographer, but perhaps it's the best example I currently hold of what can be achieved in post processing.
Point is ... the image was captured with poor light? Fear not, you may still attempt a rescue! Again, I hope I don't accidentally send out a message saying that setting up your light right doesn't matter, or being careless about your exposure is acceptable. *Note: If this had been captured years earlier or using a different camera system, I might not have attempted to retouch this image. Why? Because the light was bad! :)