your query says ur child came all of a sudden with raised skin discolouration.. no fever
..just check out if he is having any itching sensation there ..mostly raised patches will be due to allergy
or any reaction due to sunrays ..if ur child has been playing outside in sun for long this might be the cause ..just apply steroid
ointment if having itching.. and avoid sunlight for few days and if it reduces .. then avoid sunlight further by taking precautions.. just monitor if the patch is getting bigger or smaller and consult skin doc if getting bigger ..
thank u ..