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The swelling is most likely a heamtoma. I assume that you do not have any difficulty in walking or raising the legs. Haematoma is an organised collection of blood from the wound. Small hematomas (as in your case ) usually resolve by itself and no interventions are needed. Larger ones and long standing one may need surgical drainage.
There are no OTC options available other that advil. Advil in addition to its pain relief , provides anti inflammatory action which can help in reducing the inflammation around the swelling.
In case if the swelling does not show signs of resolution in 4-5, or if there is increase in size of the swelling or if there is pain or any trouble in walking or any discolouration lower down the legs you should get medical help
Hope this help
Feel free to ask followup questions.