Try to remove your Carrie suit

The letter to your former self made it clear that it's fairly easy to take off a costume made from someone. There's a tiny little lump under your Carrie skin into which the zipper pull of the Carrie suit disappeared, and you (nobody else but you, the person now being Carrie Ma -- your boyfriend, for instance, wouldn't be able to) have to prod at it for a few minutes, pinch it once it starts to enlarge, and eventually it will pop open to reveal the zipper pull. Then you can pull it down and the process that recreated Carrie by combining the costume with your former body will be reversed and you'll be your former self in an ill-fitting Carrie suit you can take off. You can zip the costume up with nobody inside, and after some minutes it'll be Carrie again, with no memories of becoming a costume or of what you did as her.

On one hand, you love being Carrie and enjoy how as Carrie you get real pleasure from things your former self dislikes. There's this core of former self swathed in thick layers of Carrie self, and its constant mix of pleasure and discomfiture at being carried along on the sheer tide of being Carrie lends a constant thrill to living Carrie's life. You're enjoying that life more than the original Carrie did! And yet...

That toast you made to "the new you." Did you mean it? Do you really want to be ten years older? Your boyfriend seems to be headed for a proposal of marriage... would you accept it?

You feel carefully at the nape of your neck. There's nothing obvious, but you were able to find a miniscule lump before as you sat on the toilet in the staff bathroom reading the letter meant for your former self... ah, there it is, just below your hair line, deeper than you remembered, and smaller. It takes what seems a long time of prodding and rubbing at it for it to start enlarging, though it's probably under five minutes. These people-suits can't be taken off by accident! You pinch the enlarged lump, now at most a quarter of an inch across and apparently very hard, as hard as you can between the thumb and forefinger of your Carrie right hand. Something gives, and you give a cute little squeal of pain (but the pain is brief and ends soon and abruptly)... and there's a zipper pull on the back of your neck. You take hold of it and unzip your womanly skin a few inches, then stop as you feel your Carrie Ma self fade away and your former male self reassert itself... your body starts to enlarge as your Carrie skin begins to separate from it...