Amother brings her three-year-old daughter to her pediatric office stating that the girl has had fever and chills for three days. the girl also has a large, intensely red patch with a distinct margin on her leg and a nearby swollen lymph node. when the health care provider touches the area, it is firm and warm, and the girl screams in pain. based on these observations, the provider makes a presumptive diagnosis and begins treatment. part a based on the observations given, what is the probable diagnosis made by the health care provider?