Welcome to our Forum.  I will be pleased to comment on your questions. Before I do however, a few general statements.  The events you describe did not put you at any risk for HIV or other STI.  both receipt of masturbation (i.e. a hand job) or participating in masturbation of a female partner (i.e. "fingering") are no risk events so that, even if your partner had HIV (which is statistically unlikely), there is no risk of infection.  this was safe sex.  It was safe even if the cut on your finger had been present before the event or even if the cut occurred at about the time you started to masturbate her.  Still no risk at all.  there is no need to even test after an exposure of this sort.  Now, on to your other questions:

1. Considering I was drunk I cannot assure 100% that the condom covered all the time my injured finger. Assuming that at certain point some vaginal fluid was in contact with my "fresh" wound would that represent for me a risk? Should I be worried? Is it even possible to get HIV like this? 

Even without a condom, what you describe was safe sex with no risk of HIV infection.  this is true even if you got some of your partner's genital secretions on your cut.

2. Can my symptoms be ARS? 

No, these symptoms are only part of those describe for the ARS, are too mild, and have occurred too soon after your event to be the ARS.  When people have the ARS, typically starting a week to 10 days after exposure, they have high fever, severe muscle and joint aches and a bad sore throat as well as other flu-like symptoms. 

3. Can I have sex with my wife without protection?

Certainly.  There is no risk of HIV from the event you have described.  I would not hesitate to have sex with your wife because of the events you have described and, as I said above, there is no medical reason for testing.

I hope these comments are helpful to you.  EWH

1.  The lump you feel on your testicle does not sound like any STI at all.  Further, nothing about the exposure you reported places you at risk for infection.  I suspect what you have felt is something other than infection- perhaps a benign, non-infectious cyst.  It also certainly not a wart as warts take months (three on average) to appear. 

2.  No, what you describe is not an area where lymph nodes occur.  I am confident that what you have described is not HIV or any other STI that you acquired from the no risk exposures you have described.  EWH

As outlined by Forum guidelines, this will be my third and therefore final answer.  This thread will be closed later today.

The answer is that both of the facts that you mention contribute to my confidence that you were not infected with HIV by the activities you described.  There are NO documented cases of HIV acquired through receipt of masturbation, despite the fact that millions and millions of people have engaged in masturbation with infected persons- NONE!.  Secondly, cuts and scrapes begin to heal immediately after they occur, sealing off the blood stream from possible infection.  Thus any HIV that might have been present (remember, it is unlikely that the CSW you were with even had HIV) would not have gained access to the bloodstream to cause infection.

I suspect your stiff neck represents tension due to your anxiety.  Please try to set your worries aside.  EWH