If you take something like omega 3, it's supposed to decrease inflammation in the body/lips which could be a cause of EC. It's good for your body overall to decrease inflammation so it might be beneficial even if you didn't have EC.
I read somehwere that flax seeds are not really a good source of omega 3 although it has omega 3. I forgot what about it cancels the omega 3 out. So, I would take chia seeds over flax seeds.