Several questions have piled up about diabetic neuropathy, and I thought I'd tackle them all in once. First of all, let me point out that there are several forms of nerve damage (or in doctor-speak, neuropathy). The form that most people with diabetes (PWD) have is damage to the nerves that provide sensation from the far ends of the body, particularly the feet; this form is called distal sensory neuropathy or peripheral neuropathy. There are other neuropathies, such as those affecting the internal organs of the body (called autonomic neuropathy), including the gut, bladder, and heart rate and blood pressure regulation. Yet another type is of neuropathy is called a mononeuropathy: a single nerve being damaged; one form of mononeuropathy that occurs in both PWD and folks without diabetes is called a "sixth nerve palsy" where a single muscle controlling eyeball movement is affected; this may spontaneously resolve over a period of months.
The painful sensations (called dysesthesias or parathesias) that are associated with diabetic peripheral neuropathy may disappear over time. Sometimes this is due to improvement in diabetes control (for example, there are numerous reports of improvement in diabetic neuropathy after successful pancreatic and renal transplantation); sometimes it's due to medications that block the pain. True reversal of the damage to the nerves seems unlikely, and people who report that their pain is gone may have had further deterioration of the function of the affected nerves to the point where no sensation is present (anesthesia).
Definitely yes. One variety of diabetic neuropathy, called diabetic mononeuropathy (damage to a single nerve) can affect any nerve. The most common cause of thigh numbness without other symptoms is compression or irritation of a nerve called the lateral femoral cutaneous nerve that supplies the skin of the upper outer thigh. This condition is sometimes called meralgia paresthetica. Diabetes is one of the causes of this condition. Treatment is to relieve compression if present, and to control BG if diabetes if present.
Although numbness of the thigh may be due to diabetic mononeuropathy, I'd be concerned that severe pain in the hip is due to something else. I'd suggest you discuss with your physician.
The mechanism of developing diabetic neuropathy is not clear. One thought is that diabetic neuropathy results from injury involving the small blood vessels that supply nerves (vasa nervorum). Others have speculated that increases in stuff called advanced glycated end products, or of protein kinase C, or stuff from other metabolic pathways, are involved. No matter which, the usual thought is that the development of neuropathy is somehow related to prolonged hyperglycemia. Of course, one can speculate that such injury could build gradually over years of mild hyperglycemia which would not be reflected in recent measurements of A1C levels.
Yes, peripheral neuropathy is described in the U.S. Product Insert for Zocor (simvastatin) --along with a zillion other events that have been reported. However, I'd be worried that the problem you are discussing might be a different one: myopathy (muscle damage) which can cause muscle pain, tenderness or weakness. Discuss with your physician!
There are several thoughts on what you might do -- see my previous essay, Painful diabetic neuropathy, for some suggestions.
Many physicians have seen and treated cases of diabetic neuropathy, and would be able to advise you as to whether you have it, and to run tests to diagnose it if needed, and advise you as to how to treat it. If a specialist is needed because of confusing findings, your physician may call upon a neurologist, orthopedic surgeon, podiatrist, endocrinologist, gastroenterologist, or even a neurosurgeon, depending on what's going on.