The correct answer is C. Imaging and surgical consult.
This lesion in concerning for necrotizing fasciitis. This should be promptly ruled out with imaging and a surgical exam. A deep punch biopsy (double-punch) to evaluate subcutaneous tissue could eliminate calciphylaxis and/or an angio-invasive fungus, but this will take several hours to result at least. Similarly a swab will take several hours to days to provide useful information. Doxycycline is likely insufficient and steroids are no indicated currently.
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