BTW nerve rings are not a sign of weakness, everyone from early childhood has them to some degree. They are caused by repression of drives and emotions. Repression usually involves fear which is linked to the kidney/adrenal system. Nerve rings can be traced from different organ systems and usually go to the kidney showing fear of the emotion. I learnt this from TCM which links the kidney to fear, the liver to anger, the lungs to sadness and joy to the heart. The left hand side is the inner feeling (feminine) and the right hand side is the expression (masculine).
The fact that to have no visible kidney energy deficiency suggests that you do not have too many repressed emotions which can damage the kidney energy and mood.