Thanks for the query,
Your toddler has developed a hypersensitivity
to mosquito bite,
It is called as papular urticaria
Apply a mild steroid lotion like desonide
Give him an antihistamine syrup.
This will give him some relief.
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.