Reflecting back on vaccinating my own animals, several of the vaccinations involved injecting a liquid into their noses. I don't recall which vaccinations exactly, it's been a long time. This was the method tested and approved by veterinarians.
My quibble isn't with the method of administration, it's with this being essentially a one off experiment each time it's done, vs the work that goes into proving immune response and effectiveness and consistent manufacturing of commercial vaccines.
Makes sense. I have conflicting thoughts on biohacking. One one hand, the people doing it often have little scientific background and have very dodgy testing methods. On the other hand, if people are open to self experimentation, they could accidentally stumble onto something great. Or bad. Or random unintended findings or consequences. I could also see businesses being intimidated by these practices, as these people could render some chemicals obsolete, also by mistake. So many pros and cons.
Revisiting this, the difference in definition between vaccine and inoculation probably isn't so big. I think colloquially it is a good difference here.
You could call it an inoculation. I think it is okay to reserve 'vaccine' for something a bit more fine tuned and tested.