A patient develops a lesion on the lower lip the day after local anesthesia. What is the most likely cause?

A patient develops a lesion on the lower lip the day after local anesthesia. What is the most likely cause?

• A. The patient bit their lip
• B. A reaction to the anesthetic
• C. An infection from the injection
• D. Dry mucosa from dehydration

Answer: (A)

Numbness from local anesthesia can lead to self-inflicted trauma, such as biting or chewing the lip without realizing it. When the lip is temporarily insensate, a patient may bite the tissue and create a minor traumatic lesion that becomes noticeable the next day as swelling and healing begin. This explains why a lesion on the lower lip appears after anesthesia. An anesthetic reaction would typically present with immediate or systemic signs rather than a localized lip lesion that shows up after a delay. Infection from the injection would usually bring redness, warmth, and possibly discharge, not a simple post‑anesthetic bite wound. Dry mucosa from dehydration can cause dryness or fissures but doesn’t account for a discrete lesion arising from numb tissue. Counseling patients to avoid biting while numb and to inspect the area as sensation returns helps prevent and manage this common outcome.

Numbness from local anesthesia can lead to self-inflicted trauma, such as biting or chewing the lip without realizing it. When the lip is temporarily insensate, a patient may bite the tissue and create a minor traumatic lesion that becomes noticeable the next day as swelling and healing begin. This explains why a lesion on the lower lip appears after anesthesia. An anesthetic reaction would typically present with immediate or systemic signs rather than a localized lip lesion that shows up after a delay. Infection from the injection would usually bring redness, warmth, and possibly discharge, not a simple post‑anesthetic bite wound. Dry mucosa from dehydration can cause dryness or fissures but doesn’t account for a discrete lesion arising from numb tissue. Counseling patients to avoid biting while numb and to inspect the area as sensation returns helps prevent and manage this common outcome.