Anesthesia does feel like acid. You can feel it coursing immediately following injection. It also tastes metallic. Some people (like me) are more resistant to anesthesia type drugs. Anesthesiologists have not been surprised when I am still talking after it's been injected into the trap. My system has held off going unconscious for about a minute. I've never made it past that. I've had more than a dozen surgeries requiring general anesthesia.
It does not hurt other than a mild, but noticeable burning feel.
Before my surgery, the cute little nurse said, “Time to give you the *I Don’t Give a S*** Shot.” She stuck me, and she was right.