When using the regime, you skin will become dry and somewhat irritated. Using moisturiser will reduce the dryness that occurs when using BP. Some people claim that their oily skin becomes better when the use moisturiser as it somewhat 'tricks' the skin in producing more oil, however im not going to argue whether this is true or not. It sounds like the dermatologist has prescribed you a treatment, moisturisers are your choice. if you follow the regime instructions (even if using your own products) you should have results. I personally think that moisturising is mandatory, however, of course their are people who will completely disagree, you really have to se for yourself and make the call. Best of luck.

The regimen is a form of treatment using benzol peroxide at 2.5%. You can follow the regimen using non acne.org products but only if they are the same as what the regimen describes. Epiduo can not be used if you are following the regimen. Epiduo is a product that combines BP and adapalene and so it is not the same thing as using BP alone.

I would suggest that if you have gone to the trouble of seeing a dermatologist, then accept their recommendation and follow their instructions precisely. If they have asked you not to use a moisturiser then I would say not to use one. But don't start confusing yourself with following a part of The Regimen and a part of the regimen your dema prescribed.

Good luck!

ps. your English is perfect.