Self Harm; Most effective methods without leaving scars?

[ForsakenDial]

Title. What is the most effective method with minimal trace?

 

[MidnightDream]

Physiologically, any breakage to the skin has the potential to leave a scar. The more intense the damage, the more healing that has to occur, the bigger mark left over.
In terms of what wouldn't leave a scar, small OD, illicit drug use, inflicting harm such as bruises, etc

 

[BringMeToLife]

I put big rocks in in long socks and hit myself.