KEEP AT IT!
You've got a way to go, in case you've not gathered it.
The one good thing about 'methycobalamin' B-12 [sp?] is that it's like vitamin C in that you can't overdose. Excess goes out of you and doesn't hang around to cause problems.
Brian had posted a while ago, [humm, don't remember exactly when?] about getting a particular B-12 he wanted thru customs from the US - it was a lengthy post...Brian do you recall it? If not I'll look it up.
Don't forget tho, healing nerves takes about 10 to 50 times longer than it took for them to get damaged or die.
Hope this helps. - j