Hello,
From the symptoms it can be dermatitis skin, contact dermatitis or nummular eczema. Nummular eczema also presents as itchy, red, dry circular lesions. Apply calamine lotion and mild steroid cream and take some oral antihistaminic like Benadryl. If the symptoms persist then please get it seen from a dermatologist.
I hope it helps. Take care and regards.
Also I am getting ready to start my period, could that have something to do with it?