Minoxidil at 19

I’m just 19 and last year I had 2 bald patches.  I started using minoxidil and they grew back in just 2-3 months. Then I stopped using it since and lost all of the hair from those bald spots.  Why did this happen?

Hair that grows because you used minoxidil are dependent upon minoxidil and when or if you stop it, these minoxidil dependent hairs will fall out  Just restart it.