**Core Concept**
The management of acute onset painful scrotal swelling in a pediatric patient involves a thorough evaluation to differentiate between testicular torsion and other causes such as epididymitis or a hernia. Prompt diagnosis and treatment are essential to prevent testicular loss.

**Why the Correct Answer is Right**
In the case of acute onset painful scrotal swelling, the primary concern is testicular torsion, which is a surgical emergency. The patient, a 12-year-old male, should undergo immediate evaluation, including a physical examination and possible ultrasound, to confirm the diagnosis. If testicular torsion is suspected, the patient should be taken to the operating room for surgical exploration and potential detorsion. **Option C: Immediate ultrasound and surgical exploration** is the correct answer as it is the most appropriate course of action for a suspected case of testicular torsion.

**Why Each Wrong Option is Incorrect**
**Option A:** **Oral antibiotics** may be considered if epididymitis is suspected, but this option does not address the urgent need for surgical evaluation in the case of testicular torsion.

**Option B:** **Bed rest and pain management** may be appropriate for some cases of scrotal swelling, but this option is not sufficient for a suspected case of testicular torsion, which requires immediate surgical intervention.

**Clinical Pearl / High-Yield Fact**
Testicular torsion is a medical emergency that requires prompt surgical evaluation, as delay in treatment can result in testicular loss.

**Correct Answer:** C. Immediate ultrasound and surgical exploration