Oldstyle,

"tendonitis -> cracked finger-tips"...

It seems to me that your understanding is a bit rigid.

WHat this "law" says is that if you were treating someone for tendonitis and the condition has improved, you would know that you made the person healthier if they came up with something which is more periferal as a symptom - and what exactly would it be depends on this person's individual constitution and health history, maybe a rash on the palms of the hands, or some acute cold with a lot of discharges, but obviously you cannot really "expect" any particular thing to appear - unless you are an omniscient God themselves? - and you would know that you made the person sicker if after tendonitis improved, they would end up with something more "internal", like say, subacute kidney condition with vague symptomatology, or maybe clinical depression...
But obviously the "next" state of health will not usually appear overnight, but will become clear only in the long-tern (at least several months, or more often a couple of years).

These laws are a sort of guidelines for long-term case management, and they were derived by clinical observations actually, have you discussed this with a clinician who keeps good long-term records of his patient's sates of health (like a typical homeopath would do) - before proclaiming that this is nonsense?