Nose and lip licking, yawning, and drooling are mild stress and anxiety signals. This sign needs context. A relaxed dog that drools and licks its lips when handed a nice reward is unlikely to be agitated. However, lip licking accompanied by body posture alterations, pinned-back ears, or panting suggests tension and anxiety.
Licking The Nose Or Lips, Yawning, Or Drooling