What are the Side Effects of Local Anesthesia?
Since local anesthetics are the most common drugs used in a dental office, they tested and understood very well. Because of this, side effects are very rare. However, there are a few things that could happen after injection.
One possible side effect is a blood-filled swelling called a hematoma, which might form when the injection needle hits a blood vessel. A hematoma might take a week or more to heal fully, just like a bruise on another part of your body would. While most hematomas will resolve on their own, it is always best to consult your dentist.
On rare occasions, the numbing medicine can cause numbness outside of the targeted area. If the numbness is extended and impacts other areas of your face, your eyelid, mouth or the impacted area could droop until the drug wears off.
Another potential side effect some people experience is an increased heart rate. However, this usually only lasts a minute or two. Make sure to tell your dentist or doctor before receiving a local anesthetic if this has ever happened to you.
Finally, a very rare side effect occurs when a needle inadvertently injures one of the surrounding nerves. If this happens, you could experience numbness and pains for several weeks and sometimes months. But there is good news! The nerve usually heals over time, so the pain should be temporary.