Gorch

From Memory Alpha, the free Star Trek reference.

A gorch is a large and unsightly skin inflammation to which Klingon teenagers are prone, similar to the Human skin condition acne.

In 2375, due to his exposure to the metaphasic radiation on the planet of the Ba'ku, Lt. Cmdr. Worf acquired a gorch on his nose, even though he was 35 years old. (Star Trek: Insurrection)