I usually get cold sores at least once a year and I've been getting them since kindergarten. So far I am pending to see a GI and I am still new to digestive issues. For me cold sores would always accompany a fever and as a child I would take the over the counter liquid childrens fever medicine, I also used zovirax in the past but as I got to high school I would really only rely on abreva because it was convenient. Last month I had three cold sores on my mouth but I didn't have any abreva on hand, or medicine or anything so I just left them and they went away in about a week.
They used to be difficult for me but over the years I've gotten used to them. The one thing to keep in mind with them though is to wash your hands after touching your mouth or eating finger foods, etc. that's what I was taught as a child. No kissing either.
If they get to the point where they scrab, crack, and bleed try using Neosporin or Vaseline, they help ease that.