The human body, a phenomenal piece of engineering, also faces problems the same way machines do. The skin is the first line of defence against infections and any breach in the skin can lead to serious problems. Any kind of damage to this first line of defence in the form of a puncture/cut/abrasion/laceration/ulcer/burn etc is a WOUND.
In the normal person, minor damages like cuts/abrasions etc may not cause much problems because the other lines of defence of the body like the white blood cells, the clotting system etc take action to prevent further damage.
But in cases where the immunity is weakened, there are clotting disorders or other cases where the body is weakened because of diabetes, malnutrition, obesity, no exercise, bedridden and numerous other causes, small wounds can flare up and lead to major complications if not cared for at the earliest.
Minor wounds can worsen if not treated properly.
However all wounds need care and in case they do not begin to show signs of healing within a day, medical attention should be sought.