How painful is a shot of anesthesia for ingrown nails ?

Not painful: I assume that you are referring to an injection of local anesthetic into the toe to numb it. This is called a "digital block" and if done with care is not painful. (hurts less than a dental injection.) it is possible that your doctor will "freeze" the skin with a spray instead of using an injection. I would describe it as briefly uncomfortable, but not painful.

It depends : On your pain tolerance. Similar to a root canal anesthetic.

It depents...: At times ingrown toe nail removal procedures may be performed without numbing the toe, but often, anesthesia is necessary. Often times your physician will use a cold spray to minimize your discomfort. The amount of pain that you may experience will depend on your pain tolerance and the presence and severity of the infection if present.

Somwehat: The use of needles is never very fun. The surgeon can either use local anesthesia with sedation, or may elect to use general anesthesia if the ingrown toenail is large.

Painful: Injecting a toe with local anesthesia can be very painful, but only briefly about 15 seconds.