I have a dark red spot on my breast which itches at times and if pushed, is sore. It appeared 20 days ago and has not spred. I was prescribed amoxicillin, and applied muprirocin no changes. Now 2 days using steroid cream and it seems worse. Ibc?

Stop steroid! If it is worse after using the steroid, it is either a yeast infection, or a bacterial infection that is worsening. I suspect yeast, because antibiotics did not help. But I can't say that for sure, and you need to call your doctor today and ask what to do, since your doctor examined the rash, and I have not.. If you have fever, rapidly increasing pain, warmth, or red streaks, get seen STAT.