5% never worked for me, I bumped it up to 10% and all acne went.
Make sure you only use it at night, wash your face straight after you wake up and I think you need to use an SPF mosituriser because BP makes your skin UV sensitive but not sure.
I don't recommend BP btw - if it works and you stop using it, your skin will breakout like crazy as it adjust to you not using BP anymore. BP only treats, it doesn't cure acne so find what is causing your acne and target that.