DS (7yrs) has chickenpox. First spot/blister appeared on Monday morning and then nothing else till Wednesday morning. He's got loads but most of them seem to be crusting over now. He's been absolutely fine in himself (apart from an hour or so yesterday afternoon when he was a bit teary and miserable) and has been eating well. Last night was awful - he kept waking up complaining of a bad headache and was really distressed. Gave him Calpol and he eventually settled. He's fine again this morning and leaping around like a loony. Are these headaches normal or is it something I should worry about?