Its there now because you have reached a point in your healing where somewhere in your mind you are comfortable and ready for the deeper levels of healing.

Yes memory recall can sometimes shock a person and now that this has happened you may end up having more and more memorys like this coming into your awareness.

What to do with it -
write it,
draw it
create it with clays and so on
talk about it in therapy,
follow your therapists suggestions on where to go next with this new knowledge.

(((((((((((((Time0))))))))))))
hang in there