It would be an ecchymosis. That is also bleeding into the sub-conjunctival space and might have been caused by the episode of vomiting. It's good that you have an appointment. It will be confirmed and it is not a cause of concern and will go away within a week or two. Warm compresses will help. Thanks.
It most commonly occurs due to trauma when bleeding occurs beneath the lid. Asevere episode of vomiting may also cause it. A bleeding dyscrasia or blood thinners may predispose to it. I hope it helps. Thanks.