I was at a haircut place getting my hair cut when the person cutting my hair cut their finger on a clippers (I think it was clippers, I can't remember). The haircut person left my chair to get a bandage. Obviously I did not see any large amount of blood on me, but perhaps there could have been. I was concerned that perhaps blood from this cut may have gotten into small cuts or nicks I sustained while having my hair cut and neck trimmed. Or perhaps that this blood got into some other mucous membrane somehow, such as my eyes, nose, mouth, or ears. From what I've gathered, this probably is not a risk. But my anxiety levels have been high and seeing someone cut themselves near me prompted me to make sure my understanding is correct with an expert. 

I am hoping that this is not a risky situation and that future situations like this, where I may encounter someone with a cut or other secretions are also not a risk for me.

Welcome to our Forum.  Your understanding is correct.   It is unlikely that your barber has HIV but, even if he/she did, the events you describe was a no risk exposure, even if your barber got some of his blood on your skin or another location while getting your hair cut.   

We get a surprising number of questions about possible exposures in barber shops.  There are no instances however in which a person has acquired HIV through exposures which occurred during the course of a hair cut or shave, despite the likelihood that minor cuts and nicks often occur in this setting.  Such cuts and abrasions do not carry blood or secretions deep into tissue as would be needed to cause infection.  No reason for concern, no reason for testing.  EWH

One thing you wrote really stuck out to me and maybe will to others. You wrote "deep into tissue". This was very comforting to me since I frequently worry that somehow cuts or scrapes will put me at risk.  

To test that my understanding is correct, could you answer this follow up question? When I go to the health club I sometimes shave or prepare for work in the locker room. There are multiple sinks and often it can get crowded. When someone shaves next to me I worry that they may accidentally scrape or cut me with their razor. If I did get scraped or cut with someones razor, would this scrape or cut also not count as a "deep into tissue" wound? Or at least a situation which would not be a realistic risk for HIV?

Superficial cuts and scrapes are not a meaningful risk for HIV.  this is a common misunderstanding.  There is no risk in using a sink that someone with HIV has used before you.  The scenario of someone acquiring HIV by accidently being cut by the person shaving, washing or involved in other hygiene practices next to you is not one that is associated with meaningful risk and is not something to be worried about. 

I hope this clarifies things.  EWH

One other question I had which I hope you can shed some light on and which might be useful to me and others on this forum. One thing I've seen you and HHH write before is that it takes "more than just one HIV virus" to cause an infection. In relationship to this, I was wondering: does the human immune system have any way of fighting the HIV virus when the virus is first attempting to inoculate? I understand that once HIV has taken hold, the immune system is not able to rid the body of the virus. However, I'm wondering if before the virus takes hold the immune system is able to fight the virus? I suppose one of the reasons I'm asking this is that I am a fairly healthy person who eats well and exercises and I like to pride myself on having a strong immune system. Anyways, thank you again for all of your advice. It really helped me.

You are correct.  Typically the more viruses present, the more likely an infection is to occur.  While in principle a single virus (or bacteria) is capable of causing an infection (this does include HIV), the fact is that the body has many natural defenses against infection which make this unlikely.  These defenses include intact skin and mucous membranes, enzymes and other secretions which are toxic to microorganisms (such as those present in saliva and the gastrointestinal tract) and an innate (as opposed to the adaptive immune system which produces antibodies targeting a specific pathogen) immune system which helps to naturally resist infection.  All of these things are more active and effective in healthy persons than persons who are not.  Thus good general health is a good mechanism for resisting infection and is part of the reason that infections (including HIV and other STIs) usually do not cause infection following a single exposure and are not more of a problem.  I hope this addresses the question

As you know, this is my third response to your questions.  Thus, as per Forum guidelines, this thread will be closed later today.  Take care.  EWH