Greetings. This could be some kind of a mild dermatitis or a pityriasis alba - which is a self limiting condition. I would suggest you to use a bland moisturiser like cetaphil or emoderm or venussia or any other prescribed by your dermatologist for your kid and apply repeatedly. If the lesions increase or persist or worsen - may be worth while see ing a qualified dermatologist near you. Warm regards.