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This could be due to mild fungal infection
which has become secondarily infected by scratching. Is there any scaling of that part of the skin. Any flakes. It would be wise to show them to a Dermatologist
to differentiate from urticaria
an fungal infection and receive proper treatment. As of now you can apply soothing lactocalamine lotion and take over the counter antihistamines to reduce itching. Avoid sun exposure. Drink plenty of water and eat fresh fruits and vegetables in diet.