Yeah this is very normal. Many people find they start breaking out in areas that they don't usually, and even in areas they are not applying the BP. You may find that you had small underskin bumps on your forehead that you hadn't noticed and this is them just all coming up to the surface. Just stick with your regimen and once this new breakout heals your breakouts should become less and less until you're consistently clear.
Good luck!
I recently found out that the way benzoyl peroxide helps acne, is also the way it can damage your skin. It works by destroying oil and bacteria that builds up on and underneath the skin. It cant tell the difference between good and bad bacteria, so it destroys the good bacteria as well, leaving nothing to fight off infection. I always wondered why my skin was dried out but I would still break out. I'm using Liquid Oxygen products that don't contain BP and my skin is clear AND soft. Not expensive either. *Moderator edit, URL removed - read the board rules*