Potty training my son started perfectly. First try, no tears. Then he learned to hold it in far faster than he ever learned to let it out. One day I watched my little boy fight his own body for seven hours, until he finally let go lying on my chest, sobbing, and fell asleep exhausted. I knew something was really wrong.
Then I learned pee withholding is "rare" — which turned out to mean nobody had written anything useful about it. So I was on my own. Frustration mounted. I tried everything, researched everything, second-guessed everything.
My son is three now. Our pee withholding days are finally over, but it took a lot of work to get there. Today, when he needs to go, he simply says "I need to go pee," and off he goes.
It can be undone. And you shouldn't have to figure it out from scratch like I did.