It seem that your has developed allergic dermatitis
to some contact allergen. Do not apply any home remedies
which can aggravate the situation. You can apply cortisone
cream and calamine lotion over affected area.
Use a good quality medicated sunscreen 3 times a day. Protection from direct sunlight is must . Do not apply any cosmetics which are containing fragrance in it as it can also cause pigmentation on exposure to sun light. For itching you can take benadryl or loratadine