It might be a reverse sneeze. Try searching for a YouTube video of it. If you can find one of a Havanese to watch it would be even more helpful. I wasn’t completely sure if I was seeing a reverse sneeze, even after seeing videos, until I saw one of a dog similar in size to a Havanese and it was a smaller “episode.” I think someone shared a video on the forum at one point, but I can’t remember for sure where I saw it. When it was first suggested to me that i was seeing a reverse sneeze I saw a video of a pug or bulldog and another of a large breed dog and it didn’t sound so deep and strong so I was even more confused! But now I know it’s definitely a reverse sneeze. It might help to search the forum. You can also try to video it to share or show your vet.