A 72-year-old woman with a long-standing right femoral hernia presents to the emergency department with acute onset right groin pain and vomiting for 4 hours. On examination, she is afebrile, heart rate 95/min, BP 135/88 mmHg, and has a tender, irreducible right femoral swelling. Abdominal examination reveals mild distension with hyperactive bowel sounds. Plain abdominal X-ray shows early small bowel obstruction. After 2 hours of conservative management (NGT, IV fluids, antibiotics), the pain persists and the patient develops fever (38.2°C) and the hernia becomes warm and erythematous. What is the next step in management?