I have some questions for you:
Awaiting your reply.
1. I noticed this about a week ago.
2. She isn't eating as much as she normally does but I have not been able to walk her everyday because of the bad weather we have been having. When I do walk her, she does eat normally.
3. No vomiting or diarrhea
4. No bloodwork in the last 6 months.
Dogs may lick their lips when they are feeling nauseous, anxious, or if there is underlying dental disease. This may be why she's not eating as much.
At her age it would be a good idea to have bloodwork done once a year to make sure there are no underlying liver or kidney problems.
If the behavior continues I recommend having her checked by your vet to make sure there is no underlying disease.
Let me know if I can be of further assistance.