Hi, this is Dr Sathya and I am very glad to help you with your question.
While I am sorry to see that you are suffering from these symptoms and no firm diagnosis has been given so far but to be honest with you I do not see the possibility of any definite neurological condition here to explain these symptoms.
However considering that you still do not have a definitive diagnosis it is better these symptoms are evaluated from a neurological perspective too. For the proper neurological evaluation of these symptoms you need to see a neurologist in the clinic and undergo a thorough neurological examination including the oral cavity/tongue too. After that they might arrange for certain relevant investigations too like a brain MRI, a nerve & muscle test called as EMG/Nerve conduction test and an EEG (study of the brain waves) etc. If any neurological cause is identified then appropriate treatment will be started.
You may please discuss all these above points with your clinic-drs including a neurologist for the further needful (clinical evaluation/examination, investigations like MRI, EMG, EEG etc as discussed above) and if any neuro conditions are identified it will be treated appropriately.
Please ask me if there are any further questions.
You are welcome.
If you feel the mouth gets dried too along with the other symptoms then dehydration indeed is another possibility to explain these symptoms. Kidney disease is generally suspected in these circumstances only if you urinate a lot - to explain the dehydration through fluid loss (if there is lot of urination then it can cause dehydration through fluid loss). And if you are suspecting dehydration then even if there is no excessive urination still ask your drs to do a urine & kidney related blood test to explore the possibility of any kidney diseases. Also in the meantime try to maintain good hydration and see whether these symptoms get better, if get better then obviously no need to pursuit this any further, on the otherhand if adequate hydration does not help these symptoms then seeing a neurologist is recommended to explore the possibilities of any unusual (out of the box) neurological possibilities.
Please ask me if you have any further questions.