My 9yo has hfm. day 4. stays in room. fever gone but still blisters. other son has some pimples on bottom. hfm? incubation period? still contagious?

Likely/yes: HFM is triggered by up to 3 strains of a gut virus as its skin manifestation. The virus can be found in blisters until they dry out, saliva for up to a 2 weeks and in stool for 6 weeks. When exposed, a vulnerable person is usually infected within 72 hrs but symptoms vary from unseen to dramatic. Spots in the hands/feet/mouth or around genitals can occur in only one area or all.