Your child may have a fever and become irritable, then a day or two later develop blisters on their lips and ulcers on their gums.
[rch.org.au]
Recurrent herpes blisters usually appear around the lips within 12-36 hours after the first symptoms (the prodrome) appear.
[dentalresource.org]
Fever, Blisters, Fever, Cold Sore, Fever Blister, Fever Blisters, Sore, Cold, Sores, Cold, herpes labialis, Fever sore, Cold sores lip, Cold sore (herpetic), Herpes on lip
[fpnotebook.com]