How did they "implant" those labels in the first place?
Repetition, (false) evidence, (implied) social validation.
1) They told you for years, that's easy to understand. You have to tell yourself often about the new you. try not to focus on "I'm no longer this", instead "I am me, and I am like this".
Denying/rejecting the label keeps it at arms length,
but that's not far enough for our purposes. We need to establish new ones, let go completely of the past.
2)They pointed out (still do) your flaws constantly, "see, this is why you are like I say you are". You have to realize when your new self is expressed and make note of it. You see it, you experience it, it is real. Keep experiencing your true self and it becomes easier with time.
3) Your parents told others about who you were because you were a kid and "they knew better". Maybe they just "told you" what others were thinking without much evidence. your parents certainly told you what THEY were thinking, and they were certainly a major part of your social group. That image got internalized because "others" believed that about you.
When you notice people see that new self in you, they comment on it, you notice a different reaction, they know the new you, and so you believe it further. Despite all the individualism in our society, we are social creatures and we want others to see us in a positive way, aligned with our own perceptions of ourselves.
Show the world who you are, and make note of the fact that they are seeing what you see.
Hope that helps
