My black cat had the same thing and I’ve been told by two different vets that it’s basically a reaction to mosquito bites. For my cat they give her a type of injection which helps make them go away. Also if you can limit your cat’s outside time if they are indoor/outdoor. I would take you kitty to the vet asap. These dots can get worse and if you see bleeding of any kind you don’t want to let that go on for too long. The vet may also recommend hydrocortisone to rub on the nose as well. Hope this helps!