My son was in a swimming pool for about an hour with me, when we got out, his hands and feet started to hurt to the point he was crying and had me carry him to the car. Then the next day in a bath at home, he was in the water for about ten minutes and the same thing happened and the day after he walked in a puddle of water and his feet started to hurt to the point of crying. What would cause this? I thought it was the chlorine in the pool until plain water caused it to happen.