Ds 2 and a half has a friend we were playing with about 12 days ago [they were playing a recorder and passing it between each other covered in spit obviously] Friend has now come down with blisters all over mouth and throat - mum didn't say but I'm thinking it must be a primary herpes outbreak. Just wondering if anyone knows the transmission procedure, ie, could ds's friend have been harbouring the virus when ds was sharing his recorder? And is there a incubation period beyond which ds will definitely not have it? bit worried.