Gorch (medical)
A gorch was a large and unsightly skin inflammation to which adolescent Klingons were prone, similar to the Human skin condition acne.  Data, during a conversation between Picard and Worf, cited it as a pimple in a whisper to Picard.

In 2375, due to his exposure to the metaphasic radiation on the Ba'ku planet, Lieutenant Commander Worf acquired a gorch on his nose, even though he was thirty-five years old. ()

de:Gorch
Medical conditions
Klingonese