Acne.org Products
So....for the first two weeks of the Regimen I was using Neutrogena On the Spot treatment. I got it because it was the only one on the recommended products list with 2.5% BP. Skin improved significantly the first week...stayed about the same for the second which was good...I was able to start applying twice a day and skin was not at all red or irritated, but just slightly itchy. My 3rd week I got the free kit of the Regimen to try out the products...used slightly less of Dan's BP because it was much easier to spread.
The next day no joke...my skin looked like a dry cracked lake bed. The moisturizer burned on contact. I lessened to the minimum amount once a day...and one day this week I skipped completely. I moisturize several times a day and add jojoba oil to the cleanser, which helps with dryness but it doesn't seem to do much for flakiness. Yesterday I got terrible breakouts around my chin and mouth, probably due to the irritation. Now coming to the end of this week I am no longer feeling much burning.... but my skin is DISGUSTINGLY flaky and extremely itchy .To the touch my face feels almost like it has a thick layer of glue that dried on it. I'd like to think my skin is adjusting, but I almost think that the BP simply fried my skin so bad, that I have several layers of dead skin that are protecting the deeper layers from the burn. Also, all the acne that I lost on weeks 1 and 2 with the Neutrogena BP have come back and then some.
What sucks the most...is that Dan's BP is so much more affordable than buying those .75 ounce tubes at 6 bucks a pop, but I'm wondering if my skin just doesn't jive well with it. Does anyone have recommendations? Has anyone else had this problem? 
I have had the same problem. I used Neutrogena's BP for about two weeks, and then I started using Dan's BP. It took about a month for my skin to fully adjust to Dan's BP. I lived with the flaking, redness and itchiness for about a month. What I did was I decreased my dosage of BP, added AHA+ to my regimen every night half mixed with moisturizer, and used BP less often. I had to keep starting over with Dan's BP, using a pea size and working my way up to the full dosage, but it always left me flaking, itchy, and really red. It is now three months later, and I now use the full dosage of BP only at night and then mix half moisturizer and half AHA+ at night. Using BP only at night greatly decreased it's side effects, and I am still clearing up .You might break out some right when you only start using it at night, but eventually your skin gets used to it and doesn't make you break out anymore. I think it's just that people like me and you have sensitive skin and have to use a lot less than normal people and still have the same results. Hope I helped 
Dan's bp is pharmaceutical grade so it is going to penetrate the pore easier than many other bp formulas. Also, a bp lotion is somewhat creamy where a gel is not. Please also keep in mind that the reactions you are describing are also common reactions for anyone who is new to The Regimen, even if all they have used is our products and not switched back and forth. The first few months can feel like a roller coaster ride. A breakout around week two is very common. Here's the typical "what to expect" timeline.
http://www.acne.org/regimen#expected-improvements
Bottom line, what you are experiencing may not have anything to do with switching bp but rather the usual progression of slowly ramping up the amount of bp regardless of which bp formula you are using. If you are miserable though, reduce the amount back down and take it much slower. In the end, if your skin was happier with Neutrogena on-the-spot, it's perfectly okay to continue using it.