hello, as u are giving history of your symptom and morphology it looks like a case of pityriasis rosea , a type of skin allergy(hypersensitivity) to allergens/ virus/bacteria ,u have 2 specific about history when it comes when it goes same as is any noticeable infection at the time of initiation of disease or anything else,normally this type of disease resolve within 3 to 4 months but in some case s it may persists for more then 6 months but it is rare ,appearance of lesion is important 2nd diagnosis which come in my mind is seborrheic dermatitis having similar complain , so better go to a good dermatologist and till then u can try some emollient because in both cases it will never harm ... tack care