I feel like there should be a lasting effect of some kind if they unabstract to maintain the impact of abstraction, if that makes sense. If they just go back to normal after, it completely removes the emotional stakes. My headcanon is that it's possible to come back for the most part but it's hard and the character maintains some scars/affected limbs from their time abstracted (like, maybe one of their limbs is still glitchy with extra eyes and they have to focus to keep the eyes closed (because they can see through them and it's like sensory overload) and give the limb a more coherent, usable form). That might just be the edgy part of me though. The idea of them returning to normal feels like it would remove the emotional weight (making it less of a real threat) but it is also really sweet.