superglue it back in place but ensure it is 100% clean where the glue joint is.
clean it with some light solvent first isopropyl etc, you can also bolster it after with a little araldite or similar epoxy.
When refitting the torx screw, heat it gently with a cigarette lighter first (not red hot !) but just enough for the screw to worm into the plastic softly, as it cools it will lock fine