The young boy's eyes were swollen shut and his face was blistered, a court heard.
The eight-month-old child was rushed to hospital for emergency treatment.
The woman who was caring for the child when the incident took place avoided a jail sentence at Livingston Sheriff Court.
Caroline Tonner, 34, was put under social work supervision for two years to help her deal with ongoing alcohol and drug problems.
Tonner admitted culpably and recklessly leaving the baby unattended next to a sink of hot water whereby he fell in to his injury.
The incident happened at her home in Fauldhouse, West Lothian, on April 28.
Brent Bissett, prosecuting, said Tonner went into the living room, leaving the baby unattended.