My older brother and sister got chickenpox when I was only 3 months old. I caught it too but my mum just breastfed me around the clock to help me with antibodies. The only thing I have to remember that by is one scar on my leg as I could reach that spot and scratch it without mum noticing. Mum said it was frustrating having a baby with chickenpox but now that I have had them I don't need to worry about it any more!

Like the PP have said, the infectious period is before the spots appear and the 'gestation' period of the virus is about 14-21 days. So if he was exposed 2-3 weeks ago you would expect the herald spot to appear on his head or torso about now. The most important thing is to stop them scrating the spots as that is what makes them scar. My mum used calomine lotion and it worked well but I think there are other things available now. GL