I know that L-lysine supplement works for a lot of people, my oldest son included but it doesn't work for me.
L-Lysine worked for my son, who is the only one in my family with cold sores. Acne hit only one daughter in her teens, and even that went away when she cut her long hair. Might have been caused by some of the pounds of beauty products she put on it, but it did leave and left no marks.
I think that eating a lot of probiotic foods might be a big help.
Yogurt, buttermilk, Kefir, Kombucha, perhaps even cottage cheese. And cut out junk foods.