David, I understand your reasoning but isn't an external expression a sign that a remedy is needed?
A cold sore is a sign of flagging immunity, stress, etc which causes reactivation of dormant virus (herpes Simplex) particles as is a break our of herpes zoster - or any infection for that matter. It is a herpectic viral infection, and should be considered as such.
I understand about avoiding a single symptom suppressive remedy, but I think treatment is required for this patient as they often also accompany acute infections or are prodromal to them.
http://www.animated-teeth.com/cold_s...cold_sores.htm