Hi Welcome to Healthcare Magic Forum Looks like your grandson has developed a lesion of Vector dermatitis..also known as Paederus dermatitis.. Paederus dermatitis is a peculiar, irritant contact dermatitis characterized by a sudden onset of red lesions on exposed areas of the body. The disease is provoked by an insect belonging to the genus Paederus. You need to apply an antibiotic/steroid combination cream over the lesion (something like flutibact, fucibet) twice a day. Take oral antihistamine like levocetrizine once a day to decrease the swelling (Dosage according to age of the patient) Do not use any moisturizer or oil over the lesion Do not cover the affected area Wear cotton clothes Hope it helps Wishing your grandson speedy recovery Dr Geetika Paul