I cannot confirm anything without examination but it can be contact dermatitis or allergic reaction to the chlorine
in the swimming pool water. Treatment includes epinephrine, antihistamines, or cortisone-like drugs. Take some oral antihistaminic like Benadryl and apply calamine lotion. Itching can be controlled with cold packs or commercial topical agents that contain menthol, camphor, eucalyptus oil, aloe, antihistamines, or cortisone preparations.