Thank you for your query.
Treat your son with a nappy rash
cream and some oral probiotics for 5 days.
Does your daughter go to the day care centre too?
If she does enquire at the day care centre about the strange happening.
Treat you daughter on similar lines.
If they worsen consult a specialist.
If you have any further queries you are free to consult me.Hope this answers your query.Wishing your children a speedy recovery.Have a nice day.