mark, foot print
痕 centers on a visible trace left behind: a mark, scar, or footprint that shows something was there.
痕 combines 疒 (sickness) with 艮, which likely contributes the sound and the idea of a remaining trace or mark, as in a scar left after an illness.
The sickness enclosure 疒 wraps around 艮, like a scar or mark left on the body after an illness. Picture a visible footprint or trace that remains.
For コン, imagine a con artist leaving a fake footprint at a crime scene: con -> コン, and the mark is the trace they left behind.
trace; vestige; mark; sign; evidence
scar (e.g. from operation, injection); trace; mark (e.g. skid marks)
bloodstain
fingernail mark; scratch
fingernail mark; scratch
scar; cicatrix
bullet hole; bullet mark
pockmark
smallpox
shoe print (of a suspect at a crime scene); footprint
skid mark; tire mark; tyre mark
brake marks; skid marks
sword scar
notch; indentation; crena; incisure; foramen
scar
impression; indentation
ink marks; handwriting
in bold, vivid brush strokes
operation scar; scar from an operation
extractor mark (on a cartridge)