I don't think anyone really knows all the answers about thyroid issues.

I had a patient once who had her thyroid removed and was so hypo all the time, she became so constipated, she was in agony.

TSH is made by the pituitary in response to some trigger in the tissues that signals a need for more hormone. The hypothalamus is involved too to signal the pituitary.

High TSH means the body's tissues are signaling for more hormone. It will go up irregardless of whether you have a gland to respond to it or not. It is similar to women having very high FSH (follicle stimulating hormone after menopause). In this case the ovaries cannot respond, either, so the pituitary ramps up the FSH.

In the case of treating hypothyroidism, doctors use the TSH values to gauge if your body needs more T4.

Common signs of hypo and a need for more T4, are cold intolerance, orange palms and soles of feet, hair falling out, and edema (fluid retention). Over time hypo people deposit tissue in the skin which can compress the carpal ligament and tarsal ligments. This is the basis for the PN.