Impetigo can look a bit like chickenpox. It is most often caused by Staphylococcus aureus. It is relatively contagious, but usually not serious and tends to go away on its own within a week or two.
Look for yellowish sores with crusting. They can form blisters, get wet, and itchy.
Keep wounds clean and disinfect items such as clothing and countertops. Wash your hands and feel free to use antibac.
Keep the child home from school until the wounds are gone.
You can get antibiotics if it gets bad, but it probably won't.