My experience is that I use 10-20mg daily for 1-2 months, then start to adjust or tail down after that.
I warn patients of flares in the first 4-6 weeks, which is really common.
I think that Benzoyl peroxide should be avoided. Also, you should consider moisturising more actively. I like Serums, including the Skinceuticals B5 hydrating serum which my patients on Isotretinoin seem to like. It's light and moisturising at the same time.
Don't give up! The light is at the end of the tunnel. Been through that too!