My child started with symptoms of typical allergies last Tuesday. When benedryl wasn't helping by the following Monday. I took her to the dr and they gave her augmentin for a sinus infection. by Tuesday she started running a fever that was hard to keep down even with tylenol. Up to 103.4 at one point. I took her to the dr on Wednesday and she was given a z pac. She is still maintaining a low grade fever 99-100 and now has a rash on her trunk area? What could be causing this and should I take her to the ER.