Thanks for choosing health care magic for posting your query.
I have gone through your question in detail and I can understand what you are going through.
It appears to be a bruise
and it will take time to heal. Antibiotic is just for the cover, if at all it becomes infected. Otherwise it has to heal on its own. It may take 5-7 days as well to clear. Look out for the size. If it is increasing significantly then you will have to get investigated as significantly increasing size of the bruise suggests that there is ongoing bleed.
Hope I am able to answer your concerns.
If you have any further query, I would be glad to help you.
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Wish you good health,
Dr. Srikanth Reddy M.D.