Should I take my 8 month old daughter to ER for her staph infection?

I took my daughter to the doctor last week for this skin problem..they called me on friday and told me the lab test came bck positive for MRSA. I've been using the mupirocin (sp?) ointment on it for about 3 days now but today she had a low grade fever and the spot was hard and hot. I'm worried about letting it go...should I take her to the ER? My ped didn't act like it was that serious...she said just keep putting the ointment on. What to do? Thanks