Thanks for the query.cold sore
Hence the chance for this lesion to be cold sore is rare,
Even then you take precautions,
Dont kiss your toddler until the lesion is healed.
Please meet a dermatologist
for exact diagnosis.
Let me know if you have any other doubt.
you can ask a direct question to me on this forum, following the below link.
Wishing you a good health.