If you are talking about "the child with in" as in a DID alter. That kind of "child" is trigger related which means if you are not feeling triggered (upset and uncomfortable) in your present life you will not be rerunning the memorys of being a child and being abused and the feelings that go with it, and that type of child with in will not be coming out if you are not upset and uncomfortable in your present life because you will not be dissociating from being triggered. So your brain will not rerun those memories that are in pieces and stored in the unconscious level of thinking which is what the "child with in" alters of DID is.

It you are talking about the concept of the child with in that comes with or without having DID well thats normal. Everyone regardless of a happy child hood or not has times when they get a kind of de ja vu of something in their present life relating to something they experienced as a child. It could be working on a job and the boss has called you in to his office so you feel like you did when you pulled a prank in high shcool and got sent to the principals office, or you did something wrong in high school and got called in to the principals office, or maybe you are at an adults birthday bash and you start feeling the happy feelings like you did at your sweet 16 birthday party, or the uncomfortable feelings of being the one stuck in a closet playing your first spin the bottle game, or the feelings of abuse when the situations in your present life reminds you of the past. and in this case there are alot of people who go on with their lives perfectly fine just saying ok that reminds me of bla bla situation and thats the past and I am fine now and go on with their day.in this type of situation all that matters is you recognized how you are feeling and took care of it by acknowledging it and finding a way that works for you so that you are not stuck getting overwhelmed with those feelings. If you are fine you are fine. you feel what you feel and thats you. This type of child with in does not prevent the person from growning up and having a normal and complete adult life.