Suggest Treatment For Itchy Rashes Under Legs, Arms And Groin Area

Hi my son had a itchy rash develop under his arms and legs also around his neck and private area . This continued to for five days they are going away but will it scar , maybe a picture would help? It is a lot better I don't know bit he kept waking up scratching and was upset but he doesn't feel upset in the day! It is also on his stomach but they are little tiny bites all over