Liposuction, while it doesn't break large vessels, very often injures capillaries. Also, because the mons pubis and external labia of the vagina are dependent, and since all the post liposuction girdles are open in this area, therefore exerting no pressure, for all of these reasons, the genital area tends to get significantly bruised and swollen after abdominal liposuction.
One of my female patients, after liposuction of the abdomen, called me and told me her genital area looked like an EGGPLANT, so as you can see, this is very common and it normally clears in about 10 days. DMSO sprayed on this area, but not into the vagina, can hasten the resolution of the bruising in the tissue, and therefore get rid of the black vaginal area faster.