Yes, definitely check your hormone levels, I am on a vegan diet too since last summer, I went gluten free for a month (soooo hard!) but it made no difference.
I tried everything, I even went to see a naturopath and spent a bunch of money and I still have acne. I am currently on 40 mg of accutane. This is my last resort, my acne is mild-moderate, I get huge cysts every week or every 2 weeks sometimes, I also have tons of blackheads.
i know it works for a lot of people, too bad it didnt work for you. The pill might be a good option for you if it is hormonal.