How likely is it to get herpes while the skin on the lip is red, before the initial legion appears? My girlfriend kissed me, we are always careful and reasonably educated about Herpes, but she told me 4 hours after she kissed me, that she was getting a sore. She felt no tingling before, but I did notice she had a small red patch on her lip, which I assumed was just irritation. She is on medication, we always abstain from activity when a sore is present. But I would like to know if the transmission of herpes is high from an active sore? Will it successful infect 100% of the time? Are the chances still extremely high before the legions appear?