A 7-year-old girl presents to a general pediatric clinic with a 6-day history of low-grade fever, sore throat, and a developing rash. Her symptoms began with a mild fever and throat discomfort on day 1 of the illness, followed by the appearance of mouth sores and a rash on day 2. She recently attended a local day camp. Her past medical history is unremarkable, and she is not on any regular medications. On examination, her temperature is 37.90C, blood pressure is 105/55 mmHg, heart rate is 85/min, and respirations are 18/min. She appears fatigued but is interactive. Oral examination reveals multiple painful, erythematous ulcers scattered across the hard palate, buccal mucosa, and tongue. Her skin shows a maculopapular rash with some evolving vesicles primarily located on her palms and soles, with a few discrete lesions noted on her buttocks. Considering her clinical presentation, what is the most likely diagnosis and the recommended initial management?