Lidocaine applied to the glans is generally not significantly harmful.
Lidocaine is a local anesthetic that blocks nerve conduction by inhibiting sodium ion channels on cell membranes, which in turn creates an anesthetic effect.
Lidocaine cream is often used for needle puncture or superficial surgical skin anesthesia, because of its own safety is good, and as a topical cream will not enter the body metabolism in large quantities, generally will not appear obvious harm. If used, it should be used under the supervision of a physician.
It should be noted that during sexual intercourse, the lidocaine applied to the glans will also be absorbed by the vagina, resulting in vaginal anesthesia and lack of pleasure. So improving the quality of sexual life through this method is not always desirable.