I had a pretty moderate case of acne, until I tried taking birth control for it, and it turned into a severe case of acne! I stopped taking the birth control after two months and started taking 7g of pantothenic acid (vitamin B5) a day: 7 x 500 mg in the morning and 7 x 500 mg in the evening. On top of that, I take 100 000 I.U. of the vitamin Beta Carotene: 2 x 25000 I.U. in the morning and 2 x 25000 I.U. in the evening. I noticed improvements in my skin within one week and after about probably three weeks, my skin was perfectly clear! It's actually unbelievable and I definitely suggest you try both vitamins! I'm not sure if one of them is working, or the combination of both, but either way, there's no harm in taking them! I've been on them for about 6 months now and am very pleased with my skin!
Also, on a side note, I notice that when I drink coffee, my acne flares up. If you're a coffee drinker, you may want to try stopping for a week and see if your acne clears! My skin texture changes drastically once I stop drinking coffee.
Hope this helps and please do try it!