Maybe! Iirc, frogs can't regrow limbs, but since marcy's amphibian parts are from general amphibian stem cells rather than any single species ("froggy marcy" is just an easy way to say it) , it is possible there's some axolotl or salamander in there that would allow them to regrow a limb. however.. dr s is pretty proficient at fixing injuries, i dont think marcy would need to wait for a limb to regrow haha