I look at the tattoo thing as a personal preference no different than weight preferences, or height preferences, etc. I guess you will have to decide if you are so offended by tattoos that you are willing to stop dating her, particularly if she really likes them and starts going for more of them.
For the record, I am not a fan of tattoos, either. I generally feel that because so many people are strongly turned off by them, I don't advise getting them. It is hard enough to find true love without alienating a sizeable number of people over something so unnecessary. But that's just me.
Relax... I'll need some information first. Just the basic facts - can you show me where it hurts?