Since you seem to be offline, ill leave a response here which we can discuss later on.
From what you have described this sounds like a neurological issue more than anything else, considering the hypothyroidism which you already have it is likely that you are suffering from peripheral neuropathy which is a condition in which the nerves are damaged because of several underlying causes including hypothyroidism, vitamin deficiency, infections, heavy metal poisoining among others. This would cause sensations of warmth as well as tingling or numbness in some cases. in some cases it can also cause pain however abnormal sensations are the hallmark of the disease. it can be diagnosed with the help of a simple clinical examination and also with a nerve conduction study. The treatment can involve several drugs like lyrica as well as treating the underlying cause.
Another cause of this could be compression of the nerves in the back which can cause these sensations even in the absence of back pain. This would be diagnosed with a nerve conduction study and also with MRI of the back. A condition known as meralgia parsthetica can also start as abnormal sensations on the lateral surface of the thigh.
Now i would suggest that you start using OTC vitamin B complex supplements and at the same time see your doctor for a clinical examination as well as a nerve conduction study.
Do you have any more questions?
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