It can be a mosqito or bug bite
.As calf muscles are quite active so any wound of calf skin takes more time to heal.If possible administer any antiallergic syrup like avil
or citrizine.Apply. antibiotic ointment over it so that there should be no secondary infection.Relax. your baby will be fine in 4 to 5 days.if still it persist just consult your physician.
Dr. Amit k. Gaba