Hi, I think it depends on people.
first of all, try to calculate the effective B5 you take each day.
Then try to divide dosage more times you can e.g. some pills every 2 hours.
Then you can see results very quickly. The result are not less spots, ore
better skin at the beginning!
I think the first thing you should notice afte 4 5 days with the "megadose"
is that your skin is not more oilish as before.
If you don't have an oily skin, or if your skin doesn't stop to be so oily,
maybe the problem of your acne is different
or more sever, so for last you can think about accutane and its possible
side effects.
For scientific answer try to go to
http://www.b5supplements.com/Acne-Links.htm