You searched for: “agraphesthesia
agraphesthesia (s) (noun), agraphesthesias (pl)
The inability to recognize letters or numbers drawn by examiners on the skin of the subjects who are being tested: In agraphesthesias, the patients' eyes are often closed when these procedures are performed on the skin areas that are normally visible to them so they can't see what the examiners are doing.

When a person with agraphesthesia can't feel "writing" on the skin, it is believed that it is usually caused by a central nervous system lesion. This problem is typically tested by an examiner who uses an instrument [not an ink pen nor a pencil] that forms a number in the palm of one of the hands, which the patient can't see, and then asking that person to tell what the number is.

When blindfolded, Robin experienced total agraphesthesia, and could not recognize any of the simple designs the doctor drew on the palm of his hand.