Over the weekend we noticed a small bump on the top left side of D's nose. It doesn't seem to be hurting him, but it cropped up rather suddenly. I don't think it has changed size/shape in the last few days, but he has never had anything like this so far. Has anyone else experienced something similar? The bump is about 3mm in diameter.

Luka gets a bump or bumps on her nose if she is bit by an insect or is having an allergic reaction. Her allergic reactions are almost always accompanied by extreme facial swelling. Bug bites just look like what you are describing, a bump on the face that seems to appear out of nowhere. Luka actually got bit by some bug this morning and has a big itchy bump on her snout! We give her benadryl tablets. If its really bad we take her to the vet for a benadryl injection. She also gets to wear a cone if its really itchy. Usually takes one or two days to disappear completely, but sometimes takes a little longer.