The best thing to do in this scenario is to go to the hospital for the doctors to observe the child. If the amount ingested is small and there are no complications, the doctors will just observe but if their are issues, they will treat symptomatically.
Elimination of the poison or product ingested can only be done in CASES WHERE THE PATIENT PRESENT TO THE HOSPITAL WITHIN FIRST ONE HOUR, hence the need to avoid waiting time but go to the hospital immediately.

Kindly leave the breast alone, it will resolve on it's own. It is as a result of maternal estrogen levels at work in the newborn.

But if you are still worried, see a paediatrician to rule out mastitis or abscess.

Your child needs to see a paediatric endocrinologist for a proper evaluation.

After three days of fever, the child gets a rash. If your child is drowsy, you must call the doctor immediately. Three-day fever is a highly contagious childhood disease caused by a virus. ... Already after 2 years of age, far most children have had three-day fever.