I don't get the tingle either - first I know I have a cold sore coming is my jaw glands start to swell and get sore or achey!
I use zovirax anyway despite it saying to use as soon as you feel the tingling, and do find it speeds up the healing. I also take low dose voltaren at same time and find that helps even more with the pain/inflammation - seems to stop the blisters breaking open and spreading so my lips don't end up looking too horrendous!
The small tube of zovirax lasts ages as well as you only need such a time amount (don't squeeze the tube as heaps will come out and too expensive to waste!)
