This may be of interest to you:

https://www.youtube.com/watch?v=I0B7RXCp47k
I dont have cystic acne, just spots and I'm in my 30s. So stressed I tell ya.

ANyway I did almost everything she said on the video- cut dairy out completely, taking a probiotic and L-Lysine.

Worked. I didnt need the detox part 'cause my diet is actually very clean; i dont eat much sugar or processed foods and I do workout 3-4 times a week.

But ya, try. L-Lysine in Malaysia- 21st Century brand. Bough 3 bottles for about RM90 I think.