Interesting, but that's only one view, not a before /after comparison. We don't know if her clit & clamshell were always that big, or if not then when exactly did it enlarge? Holm's been in competitive fight sports more than 15 years. If it was from PED use it's not necessarily recent.
While clitoromegally can be the result of steroid use, it's not automatically an indicator. The stress of many years cutting weight could also contribute to minor appearances of gender ambiguous features.
If she was using anything I would suspect t's drugs to help burn fat as well as to help dump weight. She is maintaining a career-low weight at age 34 of a very long fighting career and it's not like she didn't used to train seriously before. I don't remember her this lean in the upper body when she boxed. However that could just as easily be because she's stopped using stuff that bulked her up to the 140's.
Either way the win was mostly built on her movement & jab and the way she used that distance. The head kick was massively powerful but Rousey was basically done already - she had been wobly since the elbow and also gassed out - Holm actually stopped her from falling, and turned her around to steady her for the kick.
"The Book" on beating rousey might be out, but footwork like Holm's doesn't grow on trees, certainly not in the UFC Women's division. IF Rousey has the desire to come back, she'll still beat almost everyone else out there. But to beat Holm. she's probably looking at a couple of year's hard work at retooling, I'm not sure her heart will be in it for that kind of commitment.