Please go back and read the many posts on fingering. There are many about cuts on the fingers.
I say again that you cannot get an std from fingering. AND if you only fingered her, you would not be feeling affects of an std in your penis. Stds do not enter the body through fingers and certainly not through superficial cuts. If they were deep lacerations, then maybe...but I certainly would not want to be fingered by someone who had a deep laceration on their fingers. And I wouldn't think that a person who had one would want to. But that's just me.
I do not agree with 2terrified. If your finger had an open wound, STD can very well be transmitted to you if other person had it. Now the pain in your penis tip may not be related to STD as you answered yourself it may be due to trauma by pressure. If this other person had STD and you had lacerated finer you inserted in her vagina, you may as well get an ulcer on your finger rather than on your penis. If that person is still accessible it is better to confirm if she had any STD infection recently. Person while getting treatment for STD can still transmit disease to other persons untill the treatment course is complete.
Not std related. Std's do not transmit by fingering. Nor do they transmit through clothing.