Sometimes it takes up to 3-4 weeks for the Tegretol to start working. It's possible you need more time, or you might need a higher dose. If you're getting the shocks, I would definitely keep on the Tegretol and talk to your prescribing doctor if it doesn't start working in another week or two. I know it's tough.
I just wanted to add that in the beginning I had to switch to the slow release version of Tegretol, the plain ol Tegretol just didn’t touch my pain adequately enough. So give yourself a few weeks and ask your doctor or Neuro how to increase on your own in case you need too. ( hugs )