Arcane Purge

You focus the energies in your blood to flush out foreign magic from your mind and body. Choose one one spell or magical ability, that requires a saving throw, which you are under the effect of. You immediately re-roll the required saving throw to end this effect, adding an additional 2d4 to the results. If you fail this saving throw, you deal 1d4 force damage to every creature within 10 feet of you. If you succeed this saving throw, the force damage increases to 2d4.