What is my best course of action for jowls in a 40-year old? (Photos)

FaceTite can internally tighten the skin in the lower face and neck. After all the skin has been heated and contracted, we shape the neck with liposuction to give definition and remove stubborn pockets of fat. In one quick treatment, we can tighten skin, remove fat, and contour the lower face, jawline, and jowls with only a weekend of downtime.​ Keep in mind that combination approaches will give you a more significant improvement as opposed to a single procedure. I recommend getting a consultation with a board-certified cosmetic dermatologist and facial sculpting expert. Best, Dr. Emer

A mini facelift is a great option for many people to address sagging jowls. The recovery & downtime is very minimal. There are usually no drains, most people can go out the same day, you can shower the next day, there're no scars behind the ears and you can wear your hair up anytime and most patients take no pain medicine. There are never any guarantees of course with any procedure whether it is surgical or nonsurgical in nature. I'd recommend not getting into the mindset of thinking the jowls or neck skin will be 100% gone with a mini facelift or neck lift as this might lead to disappointment. It is always best to consider that an area will be improved and discuss how much with your plastic surgeon. 
Surgery is not for everyone. In today's day and age, there are many nonsurgical options to consider although surgery usually gets the most improvement specifically of the neck and jowls.
I would recommend that you see a board-certified plastic surgeon in your area that is a member of both ASPS & ASAPS and performs a lot of mini facelifts and neck lifts but also offers all the nonsurgical options such as injectables and laser treatments. Go over your concerns with them and make sure above all, you walk out of there with several options and an idea of the pros and cons to each of them as well as realistic expectations. 
I hope this helps. If it does, please take a moment to up vote this answer on the “respond” button on the top right.  Have a great day.

Hello and thank you for your question. Based on your
photograph, you are a great candidate for malar enhancement.  This can be
done in one of two ways.  Voluma is an injectable filler which can be
injected into the malar region as a temporary filler.  Malar implants can
be placed as a permanent way to gain volume in the cheek.  I always use
medpor implants with screw fixation.  Silicone malar implants tend to
have a high rate of malrotation over time.  I recommend that you seek
consultation with a qualified board-certified plastic surgeon who can evaluate
you in person.
Best wishes and good luck.
Richard G. Reish, M.D.  FACS
Harvard-trained plastic surgeon