Did you get blood tests done to see if you were vitamin D deficient? My vitamin D level was TWELVE, normal being 30-100. I'm prescribed 50,000 IU once a week.

I have taken doxycycline for a month and I've been relatively breakout free, so I can't really say if it has helped much.

Edit : I know vitamin D = better immune system, which would lead to faster healing and less prone to infection.

Have you tried taking vitamin A? If not, I'd look into that. I'm taking vitamin D & A currently, but in the past I've always seen success with just A (taking between 10,000 - 30,000 IU a day).

It isn't a magic clear skin pill. It's an essential nutrient that affects affects some of the factors that cause acne. If you aren't getting it from the sun, then keep taking an appropriate dose, but stop thinking it's a cure.