the most contagious time for contact to chickenpox is 24 to 48 hours before the lesions appear. obviously your little boy was exposed directly to them. he may show signs of chicken pox from 14 to 21 days after exposure. you may want to alert the pediatrician because he is so young. also, if you or your husband have not had chicken pox, you should watch for the lesions as well. hope this helps.