You're screwed.
If a girl has oral herpes but the sores are no longer present (sores have healed and vanished) and I kiss her, am I in the clear?
No beucase the virus can be spread even if there are no symptoms its called viral shedding
Fahamida Khabir has good practical advice in her answer.
Oral herpes is transmitted through direct contact between the contagious area and broken skin (a cut or break) and mucous membrane tissue (such as the mouth or genitals). Herpes can also be transmitted when there are no symptoms present. There are several days throughout the year when the virus reactivates yet causes no symptoms (called asymptomatic shedding, viral shedding, or asymptomatic reactivation).
More than 50 percent of the adult population in the United States has oral herpes, typically caused by herpes simplex virus type 1 (HSV-1). Most people contract oral herpes when they are children by receiving a kiss from a friend or relative.
If a person is experiencing symptoms orally, we recommend abstaining from performing oral sex and kissing others directly on the mouth until signs have healed and the skin looks normal again. Because most adults have oral herpes, we do not advise that a person stop giving or receiving affection altogether between outbreaks (when there are no signs or symptoms) simply because they have oral herpes.
Kissing mouth aka French Kissing is forever out.
Cheek or forehead kissing is OK.
Cold sores are really common. My mum suffers with them, and as far as I am aware my dad doesn't and never has. She avoids kissing him until the cold sore has vanished which takes 7 -10 days. My partner also gets them when he is stressed or run down, he has a poor immune system, again we do not kiss eachother until his have vanished. However, there is no guarantee that I still will not get them as the virus can be present without symptoms. Also, people can carry the virus but not have symptoms.
I myself get cold sores sometimes and during that time i tend to not kiss/perform oral sex on my boyfriend. After the cold sore has cleared up though it is perfectly fine to do these things as the herpes virus can only be spread via cold sores.
From experience and from asking my doctor: As long as the cold sore is completely gone it is ok to kiss etc...
I think if you really like this girl then let her know about your concerns regarding the cold sore issues. She could get some cream to put on the area to speed up the healing. You can usually tell the cold sore is gone when there are no marks and it's ok to the touch.
Hope this helped and good luck with her :)
This is how you get rid of cold soares/herpes. bit.ly/2juWTCy