Acne, Roaccutane, Oily Skin, Pimples On Forehead Around The Hairline, Exfoliac Gel, Whitish Serration

Hi , I m 24 Y. O male , I was suffering from acne ,around 5 years back , I went to dermatologist and he prescribed for me Roaccutane according to my wight , after finishing all of the drug course my acne condition is much better (it wasn t a big problem it is localized to some areas of my face) , I also have oily skin , Recently , I have some pimples in my forehead around the hairline , I don t know what is the cause of it knowing that I m using Exfoliac foaming gel as a facial wash , those pimples some time they goes away , and new one former afterwards , with whitish serration in some of them , and the rest are red in color ,