Carlos Guzmangarza (left) was convicted in 2016 of impersonating a surgeon — while smoking a cigar.

It never hurts to check the credentials of anyone who is going to be performing surgery on you. Just ask the San Francisco woman who asked Carlos Guzmangarza to perform a liposuction on her. As it turns out, Guzmangarza wasn’t a surgeon and never held a medical license; he was pretending to be a physician’s assistant by the name of Carlos Guzman.

Eagle-eyed observers might have detected one or two clues that Guzmangarza wasn’t entirely legit. For example:

Guzmangarza was smoking a cigar during the surgery;

He had the patient hold her own IV bag;

A few days after the surgery, Guzmangarza showed up at the patient’s home with a bag containing six pounds of the fat he removed from the patient and asked her to flush it down the toilet for him — possibly opening the door to a novel marketing campaign of “Flush That Fat Away.”

He treated the patient’s daughter for acne by giving her injections in the face with an unknown substance that made her condition worse.

When the patient’s abdomen became infected, she sought a second opinion, and that’s when she learned the reason why she got such a good deal on the cost of her plastic surgery.

Guzmangarza was charged with practicing medicine without a license, assault with force likely to cause great bodily harm and battery, false impersonation, identity theft and grand theft. While those charges were pending, he was also arrested for sexual assault after telling another patient that it was all part of the treatment of her skin condition.

In total, he was found to have performed illegal surgery on nine different women, some of whom he also sexually assaulted.

The would-be doctor was convicted in January 2016 of 33 felonies and 8 misdemeanors and was sentenced to twenty years in prison. That should give him plenty of time to study up on proper surgery techniques.