It is recommended to upload well-lit images of the red plaque on your son's face for further assessment. If the lesion is localized and your child seems to be in good general health, applying a fragrance-free moisturizing cream like Aveeno or Glaxal Base may be sufficient. It is common for babies to have temporary skin reactions, so observing the situation and applying the cream 2 to 3 times a day should help. If you have any other questions, feel free to ask.