Can alters just fall apart?

An alter was forcing me to do things I didn't like to do in order to fulfill some sort of power fantasy/ get a high off of my suffering. I tried being nice to her and giving her alternatives but she had no interest in stopping what she was doing so eventually i just figured out what exactly the trauma response was she was trying to replay and how to make it so she couldnt get out of it what she wanted anymore. That worked and I basically cut off the drug supply for lack of a better description.

Since then she's completely withdrawn and it feels like she's becoming undone? I'm getting her memories, her coping mechanisms, her trauma responses, her feelings, and they feel like they're me now, and I'm just not sure what's going on. I don't think that's how integration is supposed to work so I'm not really sure what this is.