I fell while hiking one day and scratched my thigh. A black and blue discoloration developed around it shortly after. It is now 3 days later and the discoloration is now purple and red. My concern is that a smell seems to be coming from it. I recognized the smell as the same smell that came from my aunt's mouth after she got a wisdom tooth removed and her gums were still bloody and healing. Is this cause for concern and how do I get rid of the smell?