Oh gosh, what a tricky spot you are in. It's that age old question - am I bad friend if I don't say anything or will she think I'm a bad friend if I do?  I was once faced with a situation where a friend was wearing an Ed Hardy shirt, which doesn't compare to plastic surgery, but hear me out. I was so taken aback by her outfit I just couldn't broach the subject. Seems silly in comparison to what you're faced with, but the dilemma was ultimately the same. After keeping mum on the subject, I felt like an awful friend for not informing her of the social ramifications wearing an Ed Hardy shirt could have on her. She clearly didn't get the memo and as a friend I should have passed it along. But, better late than never, right? It can be terribly awkward to approach a friend about a legitimate concern like cosmetic surgery, especially after they have already undergone one or more procedures, because you don't want them to become self-conscious about their new look. Telling her she shouldn't continue down this physically disastrous path can be detrimental to your friendship, yes. But not saying something could be worse. 
  
Your friend is obviously going through a little more than a mid-life crisis.  I would say that for whatever reason, she has become insecure.  Is she in a failing marriage?  Or newly single?  Often times, when women turn to plastic surgery it's because they're looking for validation or attention.  If she is attached, she may feel as though she's not receiving the kind of attention or appreciation she longs for.  Or worse, she could be worried about losing her man's love to another (perhaps younger) woman.  If that may be the case, surgery is definitely not the answer and certainly won't bring her any closer to her lover.  Other times, when an woman finds herself newly single, she might have breast augmentation or Botox, as a fresh start to this new chapter in her life.  I wouldn't be so worried about that – but plastic surgery can be a slippery slope.  Once an individual gets something done and it's a success, they wonder what other areas of their body could be improved.  It's similar to piercing or tattoos.  It can be addictive, and one can lead to one more and so on.  Clearly, it has already gone that far, which is why you need to gather the courage and sit her down for a one-on-one.

Suggest to your pal that her recent improvements, though successful, were unnecessary.  Advise her that she doesn't need anything else done to look great, and that you worry she will end up looking like a completely different person – and go on to regret it.  She won't want to hear any of this, but if you broach the subject with the utmost sincerity and sensitivity, she may be hit with reality before it's too late.  You might want to ask her what all of this is really about as well.  If there are deeper issues, talking it out might help her to realize them and maybe even seek help.  Sometimes women get caught up in their distorted self-image they forget to work on what's important, and that's their mental stability and true happiness.  Hopefully you can talk some sense into your friend before it's too late and she regrets all of the abrupt decisions she has made.