Biotin can break certain people out.It has to do with bacteria in your gut so it is really not surprising since bacteria feeRAB off oil and causes acne.
Seems most people can handle small doses of it,but it is really not something most people are deficient in so large doses are only putting you at more risk.
I have mild acne anyways,but when I was on Biotin it got so much worse.As soon as I stopped using it,and my body readjusted I was fine again.This happened 3 times before I realized what was causing it.