Before I start I shall give you my own definition of severe acne.
My definition of it is either nodular or cystic acne.
Both of which are very serious cases of acne.
Benzoyl peroxide is always a highly recommended treatment for acne.
But is it useless standing against the almighty cystic acne? Let's see.
It has shown tremendous results for many mild acne patients (those with blackheads and whiteheads), but, for many cases of serious acne problem, it seems to be ineffectual.
Benzoyl peroxide alone is not going to cure your severe acne.
You need a higher level of treatment like topical antibiotics or accutane in order to treat your serious acne problem effectively.
Allow me to explain, topical treatment only tackles the external effects of your acne, it does not prevent your acne and does not tackle your acne problem from its roots.
It kills bacteria on acne sores (that's externally) and also unclogged clogged pores (that's also externally).
Without tackling the problem from its source, benzoyl peroxide will never cure acne.
Hence the only way (Yes, the only way), to treat severe acne, is to have inside out treatment, also known as internal treatment.
You need something to tackle your acne problem right from its source, which is inside your body, and only then can you stabilize your severe acne condition.
If you are able to control your acne condition, topical treatment can then be used effectively to treat your acne sores.
What I want to conclude is that benzoyl peroxide is rather ineffective against serious acne cases.
Don't ever depend on it, or any other topical treatment, for serious acne issue, that is if you don't want to be disappointed.
But you can still use it for your severe acne treatment to reduce your acne lesion swolleness, but the applied amount to a lesser extent.
Benzoyl peroxide has the same side effects as most of the high level acne treatment like accutane, which is skin irritation.
Thus, using it would further worsen your skin condition.