How should I treat black widow spider bite?

Local care. The majority of patients who experience a widow spider bite require only local care of the lesion. Patients with severe envenomations could require supportive care and monitoring for complications. General measures following a bite including cleaning the area with soap and water and oral pain meds. Treatment of muscle spasm and tetanus prophylaxis may be indicated as well.
Agree w Dr. Ekizian. Black widow spider bites can cause localized pain. This can lead to cramping of muscles in the area of the bite. Or there can be generalized cramping of muscles, nausea, vomiting, abdominal pain, chest pain, difficulty breathing and tremor. If pain is significant or you have generalized body symptoms- seek medical care. For severe symptoms call 911.