Is 12 cc Juvederm an excessive recommemdation to treat hollow eyes and nasiolabial lines ?

12 c is excessive for most people.  Of course it would depend on the size of your face.  If you are not seeing the results, the material may be injected too deep.

Review of the most recent studies of Voluma, the average number of syringes used were 4. A total of  4 cc for facial rejevenation. 9 cc is well above the standard for facial rejuvenation. I rarely use 4 cc to restore facial volume. The tear trough is a small area which rarely requires more than 1 cc of hyaluronic acid. I prefer restylane or belotero for this.