The memories will always be there because memories are stored in the brain forever and permanetly unless the person experiences something physical like a massive hit on the head that damages and kills brain cells.

With DID the racing thoughts is one of the brains way of integration - having the person remember what happened in the past and being aware of the past feelings thoughts and actions while being aware in the present.

To stop this one situation -
First try to locate the triggers - something in your present life has reminded and matched with those pieces of memories. So your brain is on a type of autopilot of rerunning the audio memory pieces. Once you find the trigger do grounding techniques and relaxation to calm and then take care of the trigger - that may mean walking into another room, going for a walk away from the trigger, or in some way - throwing in the trash, rip up, put in a closet whatever but removing the trigger if possible.

If you can't find the trigger and relax yourself by noticing and taking care of the trigger try saying to yourself -

"ok that may have been true years ago but now I am an adult, if no one will give me those things then I CAN give them to myself" and then do something nice just for yourself. It could be a bath with bubbles, watch a kids movie, wrap up in a blanket and lay in pillows that are in a V shape to simulate holding yourself, listen to music, whatever will calm you.