Thanks for all these additional details.
I am sorry to hear about your problems.
Well, your symptoms sound to be related with a condition Carpal tunnel syndrome.
It is caused by compression of the nerve which controls sensation and movement in the hands , called as median nerve.
This occurs due to continuous compression of nerves in carpal tunnel in the wrist.
Your doctor may suggest, Electromyography test, It can check how median nerve is being compressed and the effect it is having on your symptoms.
The line of treatment is-
1. Wrist splint. It has to be worn at night to support the wrist and keep it in the same position. You should continue with it.
2. The use of Nonsteroidal anti-inflammatory drug such as ibuprofen, also helps in relief from the symptoms.
3. Physical therapy will also be helpful. It includes- Short wave diathermy, Infra red, Wax therapy. This would be helpful.
4. Also the use of Vitamin B6 (pyridoxine), is very helpful.
5. In case, symptoms doesn't improve then Corticosteroids can be prescribed. Sometimes, anti-depressant drugs are even prescribed to get rid of numbness.
6. You should avoid over exposure to cold temperature.
You should not use guitar for long time. You can take frequent breaks.
Please follow above measures, and consult your primary doctor for further evaluation.
Hope this helped
If you have any further question then you can ask me.
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