What Is The Red And Spreading Blackhead On The Cleavage Area ?

Hi, I have a blackhead on the cleavage area that usually drain every couple of months. But this time it isn t training and the skin around it and underneath it has become red and is spreading. Just when this was spreading over the last 3 days, I also started to get really high fever and chills and pains all over my body. Initially this bump was throbbing but now it is not. I am just wondering if it could be a skin infection or something else? Any suggestion would be appreciated