Hello dear, thanks for writing in. It looks like you have had an allergic reaction to something the skin of your privates has come in contact with. Do check for anything that you have used newly like inner wear, any chemicals or cosmetics. Keep area clean and dry. Wear cotton undergarments which is not too tight. And do consult a dermatologist if things dont improve in a day or if you develop increased swelling or pain or fever which points at a possible infection that could be spreading and needs to be looked into immediately. Hope this helps. Take care !