I have not seen blusters like that but it could be a bite or reaction to something. However, there are autoimmune disorders than can cause these types of things on the leather of the nose.
Do a Google search for "pustules on a dog's nose" and you should be able to see photos.
Look up Vesiculopustular Dermatoses in dogs, for one.
I would not attempt to put too much on it other then maybe washing with a mild soap and water or just water and keep it dry. I would also keep the dog out of the sun. Problem is too, most anything you try to put on, the dog will lick off.
I am sorry you can't afford a Vet. Perhaps you could borrow some or check into Pet Insurance, etc.
if this does not clear up or gets worse, only a Vet can diagnose the condition and it MAY involve scrapings, biopsy, blood work, etc. that would be the only way to diagnose a possible autoimmune disorder.
Any chance you are using plastic bowls for the dog? If so, switch to stainless steel or pottery.
Good luck and please update