I'm an ABPS-certified plastic and reconstructive surgeon and a member of our national aesthetic society (formerly ASAPS).
Don't do these so-called "fellowships" geared for non-core physicians. Stick to what your training enables you to do.
If you're a general surgeon without additional subspecialty fellowship training, practice general surgery (hernias, gallbladders, appendectomies, trauma), not liposuction and not Brazilian butt lifts. Doing a one-year fellowship sponsored by a non-ABMS recognized 'Board' is a recipe for unsafe surgeries and worse, patient mortality. Simply Google 'BBL Miami death' for a deeper dive.
If you're ENT (Otolaryngology) trained and go on to do an additional fellowship in Facial Plastic Surgery, then you're well within your rights to get Board-certified in that specialty. But don't start operating below the clavicle doing breast augmentations! The only things and ENT should do below the clavicle are harvesting rib for rhinoplasty or a free fibula for head and neck reconstruction.
Having done three years of general surgery, three years of plastic surgery, a year of aesthetic fellowship training, and six months of oculoplastic surgery training, and now in my 4th year in practice as an attending, there are a lot of surgeries I could probably "figure out" how to do myself. But if a hospital is not going to credential me to do those things, then I probably should not be doing them. This is the problem with non-core surgeons - they will happily spend their weekends sucking out fat, but not be credentialed to manage a complication like uncontrolled hypertension, postop ileus from opioid overuse, fat embolism, skin necrosis, pneumothorax, bowel perforation, or DVT/PE if and when those complications occur. They simply have a call service shipping them to the ED, where a Boarded Plastic Surgeon like myself has to clean up the mess, if the patient comes out of the situation alive...
I am also a licensed attorney who regularly helps review both plaintiff and defendant cases. Imagine the worst thing that could happen, and imagine that it's YOUR name in a lawsuit. How will your lack of appropriate credentials look to a jury? Simply because it is legal to do something under your state medical license does not equate to it being appropriate for your level of training, or ethical, or moral.
I treat my own patients as if they were my own family members on the operating room table. If I wouldn't recommend my own family members to see a surgeon without the proper training, then I do not think that kind of surgeon should be performing cosmetic (aesthetic) surgery, as innocuous or benign-seeming a procedure might be.
We're Board Certified because we are rigorously tested on handling the worst possible complications that could happen to your patients, both in real life during residency and during the final Oral Examination, after submitting nine (9) months' worth of our own portfolios of cases, representing an appropriate depth, breadth, and complexity of plastic and reconstructive surgery.