Just my opinion and observation from keeping western hognose for years. I've been keeping and breeding hogs for 6 years. I have never been bit, never! They hood up, hiss, and get real showy and then strike with their mouth closed. Whenever they strike in defense it has been with their mouth closed. I have come close to getting bit several times. It has ALWAYS been at feeding time.
I am thankful that someone was willing to conduct this experiment, share their experience, and post the pics. It is important to note that most of us would not leave ANY snake on our hand for that extended length of time and let them chew on us. If one of my hogs bit me in response to feeding, I would not leave it on my finger/hand and allow it to chew on me. The only time I have had a snake bite and hold on and allowed them to hold on was as a result of their feeding response. This happened to me with an adult male boa and adult female brooksi. I just didn't want to hurt them, damage their teeth, or jaw. So I dealt with it.
As far as how venomous is a hog, how dangerous is the bite, etc.
I'm 48 and have asthma as well as allergies (mostly hayfever). Not a great combination when it comes to getting envenomated. I've been stung by bees, hornets, and wasp. Better than 20x and closer to 30. Mostly because of the environment, wrong place at the wrong time. Not because I was messing with them. Thankfully I do not have an allergic reaction and it does not trigger my asthma. I do however swell up just like the person in the pics. Fingers, bottom of my foot, ankle, etc. swells just like the hand in the pic and it last for days.
This is why in my opinion the bite of a western hog is no worse than being stung, no more dangerous, etc. Keeping western hogs is a lot safer than keeping bees. Try maintaining bee hives and not getting stung, even with the suit. Whenever a customer ask about this topic, I advise them of my opinion as well as recommend that they not get involved if they are allergic to bee stings, etc.
Just my opinion
John Q