What to do?

There is not much you can do with the chickenpox because a virus causes chickenpox; therefore the doctor won't prescribe antibiotics.  However, antibiotics may be required if the sores become infected by bacteria. This is pretty common among kids because they often scratch and pick at the blisters.
For that reason, it is enough to keep children comfortable while their own bodies fight the illness. Oatmeal baths in warm water provide a crusty, comforting coating on the skin.  An oral antihistamine can help to ease the itching, as can up-to-date lotions.  Trimming the fingernails short can help reduce secondary infections and scarring.