Poking into my personal interests

As mentioned in my other threads, I am very much trying to develop my inter-personal skills and all the threads would be related to enhancing my social/office interactions, dealing/handling people etc.

So, this time, it is entirely about those colleagues who poke into my interests. I have a naturally beautiful hair and try out many hair styles or for that matter even different lip shades or apparels. so, 70% of the times when I meet a new person, and the conversation has already started, they would ask me what do you apply to your hair... it is so glossy... the question pops out of nowhere. Though I am little shocked, I tend to reply some common shampoo name or based on the person I am talking to it would be "its natural, you see" and that goes into a take-it-easy thing between us both. but there are a few, who pester a lot. When I say some shampoo name, they just extend the conversation, like "we also use it, we never get it.. there must be something else.. u r not sharing with us".. blah blah blah and long faces.. I can't stand that....

sometimes, I make up so many stories out of thin air to avoid the discussion but next time, it would be the same thing again. I have had those kind of "vow.. you have a great hair" kind of compliments right from my childhood, but never really cared for it.. i always replied "thank you.." but no one really pestered me about the so called secret. But in offices, people really get bold, I don't know how. May be my hair stands more prominent than my other features but there is no reason to put me under pressure to reveal the "secret".

What I am trying to understand is, how do I evade/answer such questions elegantly and diplomatically that the same person should think twice before they ask me the same question.

And those ladies who have poked me are the ones who have smooth/soft skin, milky white skin or big beautiful eyes, naturally pink lips or women with no prominent features or a plain Jane or anyone, just anyone. I am not pointing out anyone's features here, but how decent would it be to ask them back, "what do you do to get such smooth skin or such pink lips or whatever". I am really getting embarrassed even as I type that. But, is there a more decent way to frame those type of reply questions?

Also, my hair stylist charges me in 4 digit and I really do not want to reveal those details to every tom, Dick and Harry I meet. That would be a disaster again.

That being one of the questions, the other things people ask me is, do you think those kind of trousers/salwars suit women of your size or physique? Or, When I had a break up with my ex or took a divorce from my husband, I wanted a change so, I had a hair cut exactly as yours. Gawd... I later understood that these were more of taunts and only intention is to put me down. Again, I do not meet such people on my own, but they literally come and strike a conversation with me just from nowhere. My question again is, how to deal diplomatically with such people?

Poking into my personal interests