You need to go to a dermatologist and ask for isotretinoin treatment. In the mean time. Start including raw carrots everyday in your diet, and avoid chocolate, rise and egg yolks.
My friend had really bad back and chest acne, for YEARS, and it wasn't until just recently they found out it was caused by a wheat allergy. I also had face acne, and birth control really helped! I eventually got moved to Accutane, which is some seriously heavy duty stuff, but has made a world a difference!