Sounds like a bad infection, but doubt it is cancer. Have it checked out by a doctor. They may try to remove it or take a sample to make sure what it is
It sounds painful and you have not left to see the doctor yet, run don't walk and seek medical help, don't think you have cancer that quick but it sure sounds like you should be having pain.....the best to you
You should get checked by a doctor because I know a guy that had a boil on his privates & it blew inward in his body & it caused ganggreen & he lost a testacle!!