For severe blackheads treatment, consult a dermatologist first. If blackheads or whiteheads are infected, use prescription topical antibiotics, or oral antibiotics. If comedones are not infected, antibiotics do not help.
For severe cystic acne, isotretinoin (Accutane) can be used, but it has many side effects. If properly used, isotretinoin (Accutane) can very effectively treat comedones. However it is not usually used for mild acne.
Comedone extraction is another option. A small metal and circular instrument can be used to extrude the comedone. Consult a dermatologist for advice.