The prefix for where Karen got a scar is naso-
Naso- means pertaining to the nose. Derived from nose and nasal.
Origin is from Latin - nãsus.
Refers to the organ of smell or entrance to the respiratory system.
Examples of words in which this is used is nasopharyngeal, nasopharynx, nasobuccal, nasociliary, nasofrontal, nasogastric, nasolachrimal, nasofacial, nasoocular, nasopalatal, nasorostral.