I had my male Lhasa Apso neutered nearly 4 weeks ago. He is around 14 months old now. Prior to the neutering, he was the most laid back dog and would barely woof at anything. Vets gave us the ok that he was recovering fine so no concerns there.

Since he's been neutered he's become increasingly aggressive towards other dogs and people walking by. He's become a lot more vocal, will snap at other dogs on occasions. The dog that never woofed now woofs at everything, is very loud and will often growl with increasing intensity at people walking by or at any noise he hears.

Is this normal, and will it calm down?

If not, how can I train him to reduce or eliminate this behaviour?