Well, first I find myself puzzled that you say she did not hurt you and would not hurt you yet she cut/pricked you. I sense you disagree, but that sounds like double-speak to me...
Secondly, I must first say that simply being pagan does not mean you cast spells on other people, hurt them, or even do anything with blood. That term is very broad.

However, your blood is extremely personal to you and it is also part of your life force. It could be used for a variety of reasons when considering spellcraft. It could be used in a spell to control or influence you, to gain your favor, to curse you, to increase HER strength (and drain your's), to create a bond, to separate a bond, and the list is practically endless.

I would suggest you consider discussing this with a psychic and asking them to specifically look over you and see if anyone may have done something. I would also consider discussing the matter with other pagans if you feel this could be a possibility as they might have an idea what it was all about or be able to give you advice on what you might be able to do in order to protect yourself if the spell was for wicked intentions (it would be against your will if you did not know she was doing it). If she did indeed use the blood for a spell (or do a ritual on you that very moment).

You might also consider googling something like "blood spell genitals" to see if anything that seems familiar comes up in order to alleviate any immediate concerns or thoughts.