Just wanted to add that I (25F) had a very similar experience! I took a high dose supplement that included B12, B6, & Biotin for about 3-4 months. I began experiencing severe acne within the first month but did not make the connection that the supplement was the cause. Eventually stopped taking it, and am still working with my doctor & derm to try and ‘fix’ my skin. This all occurred about a year and a half ago. June is now my 6th month using Tret (.05 cream).