UrdnotWrex,

The symptoms you describe - puffing out of the throat and abnormal body posturing with the head and neck elevated - indicate that your snake is having difficulty breathing. Whether that is due to some disease process or something more benign, I could not say. But it is not normal. Of course, that's not to say that we don't see it all the time in captive specimens.

You don't describe any of the details of this snake's set-up, but it's possible your snake is just suffering from too-low humidity. That certainly happens in the winter time more often than in the summer. Also, it's normal during part of the shed cycle for the nostrils to look plugged up simply due to the thickening of the lining which will come off (assuming all goes well) along with the rest of the shed, leaving the nares nice and clear again.

I'm not sure about your vet's competence if s/he's recommending vaseline as a shedding aid. Soaking in a little water (no more than half way up the animal's side) should do the trick.