It's a myth about dogs too. (If not, then 8 of mine are ill, and have been for years, and only 1 is healthy, as of this minute!) A dog may have a shiny wet nose sometimes but ,particularly if it lives in a warm house, its nose will generally feel quite dry to the touch, like the rest of its skin.If its nose is so dry that it is scaly, cracking or patently dessicated then, yes, it's not well.