If you receive a dental filling to repair a painful cavity, you can expect significant relief right away. Sometimes, the numbness from the local anesthetic lingers for a few hours before fading to a tingling sensation and then back to your normal sensation. Your tooth may feel sore or sensitive for a few days but this should not interfere with normal eating and other activities. If necessary, you can take an over-the-counter pain reliever as directed to mitigate this temporary side effect.