DS (5) started with a couple of spots on Thursday, and it's now Sunday and more are still erupting all over him. How long does it take for them all to come out, and how long does the itchiness last? We are doing the Piriton/eurax/calamine cream/ bicarb/porridge baths but the itching is upsetting him.....at least it's one down, two to go, the others will be next