My 2 year old daughter is having blister at the corner of her mouth since yesterday. Today i saw the blister became longer and wider. Being a hyper active girl, she is neither showing any reaction of pain nor negative behaviour. It has been only 2 days. Perhaps to early to see the symptoms of fever blister? What can i do to prevent this thing from getting worse? Or i am just over-reacting? Fyi, my daughter is attending childcare.