Keep an eye on the nose, not a huge problem if other strange behavior isn't occurring. However, if his nose is almost completely covered, take a soft wet tissue an wash it. Cats smell their food, and if he can't smell it, he isn't likely to eat it. Also make sure he has a fresh bowl of water in his eating area at all times. Some folks don't understand how important water is in a cat's diet. Once had a stray who lived on my porch for a couple of years, he wouldn't come in, he was too feral, and it had a crusty nose and wouldn't eat, and as soon as I washed it (that was fun!) his appetite increased. My spouse called the vet and I had done the correct thing.
My Nine Year Old Cat's Nose Is Very Dry And Crusty, Is That Normal Or Could Something Be Seriously Wrong With Him?
yes you should be concerned its not very good for an animal to have a dry nose because there is a fluid in the nose that helps the animal breathe I would take him/her to the vet straight away for a check up and see what is wrong or it might be what your cat is eating if its an outdoor cat you might want to keep your kitteh inside for a while and give it healthy food and change the water bowl a couple times a day.
Only purina is the best balance of fish and kibbles that cats simply love. Just make sure he is eating and drinking well. If you notice any other changes LEG IT... To the vet.