Is a cold sore life threatening to an 8 month old baby?

Baby cold sore: Cold sores are not life threatening in babies. They are benign and fairly common. Usually the baby will have for the first 6 months the same antibodies that you do, and so should be protected unless you are unusually susceptible.

Not usually: As long as pain does not interfere with feeding / drinking, then usually not. Should see pediatrician if persists / spreads / other symptoms.

Avoid spread: The virus is contagious and may enter the nasal passages and eyes. Since the baby’s immune system is still developing, use caution in handling the baby by washing your hands and avoid contact with the eyes and nose. Usually the sore heals without complication.