Hello,
Since you mention guitar playing and the hand pain along with the Neuro thinking of a pinched nerve in the neck.

I will suggest looking at our Thoracic Outlet Syndrome (aka TOS) forum.
It can be related to long term repetitive strain injuries, previous sports or whiplash injuries, with postural or hyper mobility factors, hypertrophic upper body muscles, extra cervical rib, anatomy anomalies...and more.
TOS forum
http://neurotalk.psychcentral.com/forum24.html
TOS forum useful sticky thread - a sort of crash course of info here-
http://neurotalk.psychcentral.com/thread84.html

My main question now is have you had any x ray / MRI to check for any c spine causes or anomalies?
And Dr did not rx any PT, just rx'd the meds?

Don't know if you looked it up but the med is an anti seizure med.
[Oxcarbazepine is used alone or in combination with other medications to control certain types of seizures . Oxcarbazepine is in a class of medications called anticonvulsants. It works by decreasing abnormal electrical activity in the brain.]
http://www.google.com/search?q=Trile...ient=firefox-a

If it was me , I'm not one to take meds if I don't really have to, so I would start weaning off as new dr suggests.
But also ask for MRI if none has been done yet or at least a xray of C & T spine..
also ask for an evaluation by advanced PT if dr does not mention it.
A really good PT evaluation is sooo much more thorough than what many MDs will do - PTs and chiropractors too, study the body & how it works structurally for many more hours than required for MDs.

On the TOS usefull sticky thread post # 1 has lots of therapy links & info on alternative therapies.