Is cutting your knuckles with your finger nail self harm?

Answer 1

Hurting yourself on purpose in order to fulfill a need for pain is self harm, no matter where it is or how you do it.

However, habit and addiction are different. People who pick at their nails until they bleed usually do not self harm, but suffer from a bad habit. However, if it is to fulfill a desire for pain, it is considered self harm and it should never be done. It can develop into an awful addiction that will never completely go away.