Buccal fat pad removal or Botox to masseter? 24, healthy, BMI on low end, 5'2", 105lbs

Buccal fat removal and Botox to masseter threat tow different areas of the lower face fullness and don't deliver the same results (is is like comparing apples to oranges).
Buccal fat removal ONLY improves the fullness of the ANTERIOR lower cheek, area where the buccal fat removal sits ( see video bellow)
Botox to Masseter OBLY fullness of the POSTERIOR lower cheek ( area close to the angle of the jaw bone). 
In patients with large anterior chubby cheeks, masseter to the muscle won't shelver a clinically evident result because the fullness of the anterior chubby cheeks ( buccal fat) "blocks" the shrinking of the muscle. 
To achieve a more defined / contoured facial look with buccal fat removal ( and Botox to the masseter) it is necessary to have good cheek bones. In my practice, if buccal fat removal candidates have poor definition of cheek bones, I enhance them with soft tissue fillers like voluma ( that lasts for 2 years)

Hi there and thank you for the images.  
Based on your images, you may benefit from buccal fat removal procedures that can help contour a slimmer looking face for you as well as reduce some of the volume. Because you seem young, you may want to consider the long term affects of this procedure, because as you age, you will lose fat in the face and premature removal of buccal fat may result in an undesirable loss of fat in the face. Facial volume is associated with youthfulness so having the extra volume is not necessarily a bad thing.
Masseter muscle reduction with Botox than help relax jaw muscles and make the face appear slimmer. Both procedures address different areas of the face, so it's not uncommon for patients with a fuller face to receive a combination of treatments to achieve the improvements they are looking for. 
When you are exploring the options of facial procedures, make sure that you also explore the right type of cosmetic surgeon to perform your procedure. Clear communication with your plastic surgeon is your best tool in getting the appropriate procedure that's suited to the goals you're looking to achieve. 
Hope this helps!