Oral herpes, or just a coldsore?

Before I start, yes, I know that coldsores ARE a form of the herpes simplex virus. Anyways, I've never done anything sketch before, but one of my friends has and ended up getting genital herpes warts in her mouth. I just found out about this a few days ago, and I had shared drinks with her a few times. I never really noticed or saw any sores (I wouldn't really think to pay attention anyway), but is it possible I could have gotten this just from sharing a drink with her? I've begun noticing a sore on the inside of my lip that will come and go (always in the same spot), but I also know this could just be a plain old coldsore, induced from stress or whatever. Any advice...? Are tests offered, and if so, should I get one done to be careful? I wouldn't want to somehow transmit it to my other friends if they can be spread this way.