Talk to Dermatologist on Acne Cystic

I am taking isotretinoin 20mg daily and i am on 50th day now but i am getting purging my existing cysts are not healing faster and i get blind pimples which are painful my overall skin is drying like my nose is fully smooth with no blackhead but my skin is inflamed and full of blind pimples and existing cysts.I took azithromycin 250mg(3x/week) for 2 weeks as prescribed by doctor but still nothing changed can i take doxycycline until this purge stops i daily take care of my skin with cerave moisturiser oil free,sunscreen fragrance free and also cleanse my face with gentle cleansing soap with no fragrance