Hello
Thanks for posting your query at DoctorSpring.com
I can understand your concern.
It's a bruise that you have, we call it purpura. It can be due to either trauma, intake of certain medications like aspirin etc, or due to a coagulation disorder.
I would recommend that you visit your dermatologist and let him call for a few blood tests called coagulation profile which will rule out any disorder.
The purpura will heal on its own. You can take oral supplements of vitamin c which will help in quicker resolution.
Please let me know if you have any queries.
Take care