hi
i am new to using Benzoyl peroxide and following this method in fact. I just started today
i did follow the method. however i am using acnecide from Boots and its 5% as they do not offer any lower. After washing my face and drying ect... i finally used the BP gel. It felt normal yet left a white dry paste all over my face. Its not itching nor has it turned my skin red!!! what shall i do did anyone else get this/ please help me im on my last straw with my acne . never felt so ugly in my life!!
Meya, I'm so sorry you're feeling so low at the moment, I've been there so many times and it honestly feels like life isn't worth living. This is not true, and nor are you ugly! Acne doesn't change who you are as a person, and don't you let it. Enjoy the good things in your life and put acne behind you. Be patient and it'll be sorted out 
In terms of the Acnecide, it will leave a white residue if you don't rub it in properly, but you shouldn't rub it in fully for it to work best. The sore skin will come soon, unless you are incredibly lucky and have awesome skin. The bad news is, it'll get worse before it gets better. You may see more spots for a week to a month and I'm so sorry about that, it's very common with BP. BUT make it past that and it works lovely. you may get days when you have a sore face, especially if you use more than you should. I recommend Cetaphil moisturiser after you put the cream on to soothe mainly.
There are many many people with acne, don't let it destroy you. You are so much more than it. Good luck with it all, keep smiling.