Herpes Doctor

I have a girlfriend for a while now and everytime i give her oral sex about a day or two later i get canker sores. I usualy get them on the side of my tongue and they are very paniful. the pain usually lasts for a couple of days and it hurts to eat and drink.it usualy goes away in a week after the pain dies down.Recently we found out she had the human papilloma virus(hpv) she got it cured not to long ago and i tired giving her oral sex again and i got the sore again on my tongue. I was woundering if you know what it is,what is casuing it,and is there anything i can do to prevent getting it,like is there something she or i can take,thank you