I am so sorry you experienced abuse from your grandmother. I know what it's like to wake up experiencing a flashback the way you described too. It's SO SCARY and CONFUSING when that happens.

As hard as this is for you, and I am sure you are angry about it, please know that even though you are a man, you ALWAYS had that child in you, none of us can really change that about ourselves. You deserve to finally let this out and as an adult man FINALLY help that child part in yourself "grieve and heal" this very deep hurt. Honestly, I believe that depression is a result of something a person experienced in their past that they suppress unknowingly.

Little children make mistakes, they can wet their beds and they don't deserve to be punished the way you described. Sadly, if a child is in an environment that stresses them, they are more likely to wet their bed.

This flashback may bother you for a while, not your fault. It's important that you acknowledge it and tell yourself, "yes, I remember that, it did happen, but is not happening "now". That will reduce the intensity of this flashback. However, you do need to work out how this contributed to a life long challenge for you as that is also present and it's time for you to finally work that all out so you can make peace with it for "YOURSELF".