suffix
Suffix used to indicate a visible mark or trace left behind, such as a surgical scar, injection mark, or skid mark. Often used in medical or technical contexts.
手術痕がまだ少し赤い。
The surgical scar is still a little red.
注射痕が腕に残っている。
An injection mark remains on the arm.
タイヤの痕が道路に残っていた。
Tire marks were left on the road.
傷跡 is a general noun for a scar from a wound, while 痕 is a suffix that attaches to nouns to specify the type of mark or trace.
The kanji 痕 means 'mark' or 'trace'. As a suffix, it is used in compound words to indicate a residual mark. The reading こん is the on'yomi.