I Had Total Hip Replacement Surgery 17 Days Ago. I

I had total hip replacement surgery 17 days ago. I have a bad rash on my sides, underarms, legs and back. I am taking benedryl and hydrocortisone cream. the rash looks like dermatitis. I am also having some back pain, which I thought I may have pulled by back. the rash is getting worse and I am concerned I could have mrsa, but it does look like it.