Cosmetic surgery has come a long way. What was once considered an entirely taboo topic has now been embraced by a large segment of the population. According to the American Society for Aesthetic Plastic Surgery, there were 9 million surgical and nonsurgical cosmetic procedures performed in the U.S. in 2011 alone.

Like any trend, cosmetic surgery comes with its own "rulebook" of sorts. If you suspect someone you know may have undergone plastic surgery, it's simply not polite to blurt out and ask him or her. If they have gone under the knife, they may not be too eager to share this fact with everyone they know. If they haven't, then it might put you in an awkward position.

According to Contra Costa Times, etiquette guru Mary Mitchell, a columnist who authored the The Complete Idiot's Guide to Etiquette, recently penned an article about etiquette guidelines for friends, family and colleagues of individuals who may or may not have undergone plastic surgery.

"When we change the way we look, it almost automatically changes the way others react to us," Mitchell told the news source. "It's incredibly rude to come out and ask about it. Wait for them to tell you. If it's really obvious, give the person an opening, like 'Gee, you look great. What's your secret?' And say that without sarcasm."

If you were aware that someone was going to undergo a plastic surgery procedure, Mitchell advises, another good question to ask upon their return is, 'How are you feeling?" 

No matter your opinion of plastic surgery, it's essential that you withhold judgment. Keep in mind that cosmetic procedures can often be invasive and require a significant recovery time, so it's always polite to ask someone about their health, first.

Of course, not everyone will want to keep their plastic surgery procedure a secret. Many people are very proud of their results, and will be eager to share their experiences with those who are interested. Telling others about plastic surgery can help reduce some of the stress that naturally comes along with an invasive procedure. It also may help them clear the air if they have undergone a drastic change in their appearance.