if there is a single isolated area which appears to be bruised it might be a varicose vein of the labia. alternatively one can get a bruise in the labia from a small broken blood vessel. a bike seat or fall onto bike bar can create bruising. if you have easy bleeding (e. g. from shaving cuts bleeding gums etc. ) even minor trauma can leave bruising. . certainly if the involved area appears to be enlarging you should get seen.
what could the purple area on my labia be?