Will vaseline in your nose cause pneumonia?

Depends: Vaseline is great for dry mucus membranes of the nose. One can apply it with a q -tip twice to three times a day. It can really help prevent nosebleeds, especially in the winter. But vaseline is not recommended for those who are on nasal cannula oxygen. The oxygen flow can overtime "push" the vaseline into your lungs and inflame them. But otherwise it is generally safe to use.

Possibly: Excessive or frequent use may lead to aspiration of vaseline into the lungs which can lead to pneumonia. Remember oil and water don't mix, therefore petroleum products like vaseline can obstruct small air passages in the lungs which are mostly water lined.

Extremely unlikely: It is technically possible for tiny droplets of oil to cause a pneumonia if there are enough of them inhaled deeply enough. However, the likelihood of this occurring is extremely small. I'm assuming the vaseline was recommended for use in the note to prevent nosebleed? I usually recommend using neosporin ointment applied with a qtip for that purpose. It works very well.