What To Do For Blackhead Like Appearance In The Back?

My sister has a small, seemingly 'normal' blackhead on her back She asked me to try to get it out, so I washed my hands & tried to squeeze it out, I couldnt manage to get all the pus out, it seemed to be never ending, also the pus had a smelly discharge. She has tried different ways of keeping it clean & using rubbing alcohol, etc. But it hasnt gone away.. Is it normal to have a blackhead that wont empty & has a foul smell?