Hi doctors

My english is not that good, please forgive me. I am a 25 year old man living in China. I am straight. I did not do any sex nor drug. My fear is about some recent cuts on my body that I do not known how and when they are caused. This forum does not allow to post pictures, so I try my best to describe the cuts. One week ago I found one on my chest/lower neck area. Two days ago I found another two on my right wrist. These cuts are very obvious. They are around 5 cm and look like thoses scratched or punctured by some sort of sharp object, and the skin around them are red and broken. There are dry blood in these cuts, and when I touch them or wash them, they can be prickling. I dont know if they can be viewed as superficial cuts because there were pus and blood in them when I found them. I thought superficial cut are those small scrapes that dont bleed. 

I really do not know how they are caused. At the time I saw them, they were already there, and they looked fresh because they did not scab by then, (now they are scabbed) The skin were red and broken around them. Since I don’t know the source of these cuts/wounds, I fear that what if they are caused by something with blood on it, and how long they stay on my skin.  I understand that outside environment does not have HIV virus because they can be dead when exposed to air. I just fear if they are closely contacted or rubbed or pressed by something with contanminated blood. (To be honest, I know it sounds irrational and silly, but I cant help fear that someone who is infected tries to do that to me, or have their wounds or blood contact my skin....I say this because I really dont know how these cuts are caused, sorry)

Doctors, may I ask: 

1. Do you think my cuts/wound are risky? Do I need test? I really hope the forum allows uploading pictures, so you can see my cuts. I promise they are not those small scrapes...but I dont know how to further describe.

2. In terms of the size and depth, what kind of cut or wound are risky? I read in one of your previous posts that you metioned “deep” cuts.  I don’t know what exactly is a deep cut, like stiches are needed? Have you seen cases caused by that?

3. Are there any cases are caused by random cuts/wounds in daily life?  Have you seen or aware of any?  

I swear to god I had not done sex nor drug. I just fear these random events, especially when they are related to blood. Because I read your previous posts saying that as long as you dont have unprotected sex nor share IV drugs, you will not have risk. According to this statement, do you mean HIV is something which the risk is up to us, because we can decide whether to do it or not?  I feel helpless because I definately did not do the two risky behaviors, but if it is caused by some daily random events like cuts or wounds that I have no clue at all, it is just so passive and I just cannot control it. Sorry if the questions sound silly, I am really scared and paranoid. Thank you very much for your understanding.