While cleaning of wound is your child's first line of defense against harmful bacteria like Staphylococcus aureus or Staphy, it must not stop there. While washing with soap and water can remove bacteria from the area, it doesn't kill them. So you have to take your child's protection a step further so as not to give invaders like Staphy an opportunity to attack. Ever.
Fight Staphy and go full force against wound infection by using Fusidic acid / Fusidate sodium (Fucidin®). It is a powerful antibacterial that is clinically proven, fast acting, and deep penetrating.
However, if symptoms persist, it would be best to visit your doctor.