I'm currently trying vitamins myself because I've read so many success stories. My friend had cystic acne and he cleared his skin up using a variety of treatments including vitamins.
However, the stories I've heard/my friend did not use a multivitamin, so I'm taking Vitamin A, Vitamin E, Vitamin C, Vitamin B12 (not necessarily for skin) and Zinc once a day. You might have better luck taking the vitamins separately!
Well I tried it and it broke me out.
Time to stop for me.