Help!! whats your opinion on this! 10 pts best answer?

ok so i have been using 2 prescription meds (topical) precribed by my dermatologist duac and tazorac and my face has been really oily. i went to the derm. monday and she said its prob. the duac thats making my face so oily so she switched it to benzaclin. i used it for the 2nd time this morning and my face is still oily. is this normal? like will it take a while for it to start working or should it be working already? only serious answers please