Please go to an experienced dermatologist I think it might be a case of contact dermatitis but unless yr examined in person it's hard to arrive at an conclusion. Hence I would urge the u not to give into the temptation of scratching and making it worse. You can apply a good emollient like cetaphil or sembamed cream or lotion for time being and see a dermatologist soon.

This problem is better answered by a dermatologist after examining you. A personal consultation is warranted.