Severe acne

my face have acne problems. Recently my forehead had a lump which was filled with pus and even my face became swollen. Now there is a mark left with little skin peeled of and dark around that mark. How to cure that?
My cheeks and chin have acne. I have been using benzoyl peroxide wash, benzoyl peroxide spot treatment and cera ve is my moisturizer. I use sunscreen while going out as well. Is there anything wrong in my routine because I just feel like it is not working.

Are you male? female? age?

You need to see a good dermatologist. For severe and prolonged rashes, retinoids are usually prescribed.