Lost memory after dentist injected novacane?

Not a normal problem: Local anesthetics such as novacane, are substances that produce a reversible loss of sensation or analgesia when applied to body tissues. This is achieved by interference with nerve conduction in the peripheral nerves. Loss of memory is not a normal side effect. The only way this may have happened is if it got into the central nervous system.

Nervous system: Your nervous system responds to stress often by raising your blood pressure. After injection your blood pressure went the other direction and you passed out. Low blood sugar can play a role also. Are you a nervous patient? Was the injection painful?