Would black widow spider bite go away on its own in time ?

Some do.: Black widow spider bites can cause localized pain. This can lead to cramping of muscles in the are 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. For severe pain a person may be given narcotic.