Talk to Dermatologist on Skin Problem

Ihave combinition skin half is oily nd cheeks nd chin pe kp(kerotasis pilaris) hae docter sugest me alite acne face wash , ungentem cream nd ultrawite capsules 500 gm but after using them meri kp wali skin zyada dark horai hae aur spots bhi dark horaen hain iski kea reason hae?nd what should ido to avoid irritation?