Hi there and thank you for using Petco Pet Education Center, formerly Petcoach to address your question. This is likely just behavioral and is commonly seen in young dogs / puppies. Over time, this Behavior will likely resolve or greatly reduce. you can try and apply bitter apple to the areas where Preston likes to lick and see if this helps deter her from doing this behavior. You can also use a spray bottle filled with water and lightly Spritz Preston in the face whenever she licks you and say “off!” while spraying her. I hope this helps guide you in the right direction. Please let me know if you have any further questions or concerns and I would be more than happy to help you further.