Open wounds mean puncture wounds, typically with hollow needles.
You are really worrying too much about this. This was not a risky expsoure. EWH
When people say your ok unless you had an open wound, what does that open wound mean?
No. that's the short answer.
A slightly longer answer is that:
1. you do not know when the cut occurred on your finger and,
2. given the fact that you were most likely to feel it when it occurred, it probably occurred after contact and,
3. that you do not know if your contact had HIV and.
4. you do not think you encountered any genital secretions and,
5. no one has ever gotten HIV from masturbation which is what this is, despite the fact that it is totally normal for masturbation to lead to contact with a partner's genital secretions,
you have absolutely nothing at all to worry about. This is not an exposure that justifies any concern and testing is not needed. Take care.
EWH