Cannabis for reattached finger?

2 Years ago my best friend had his finger cut off and reattached. It was not done for about 9 hours though. (2 1/2 hours to get the hospital to decide where he should go, another 2 1/2 for the ambulance drive because since he was stable he wasn't an emergency, and another 2 hours before the specialist looked at it and started the operation) Needless to say he suffered major nerve damage. He can't feel anything in it except for a constant ache in the bone. He's been on a couple of different pain killers since then and he says they help but he still has pain. He smokes but it doesn't help with the pain, and if he took his pain pill he says MJ cancels out the effect of them. He also doesn't enjoy the high from eating it.

I was thinking of trying to make a topical cream from cannabis for him. Has anyone had any experience with them? Would they penetrate deep enough to do any good? Or if anyone has had a similar accident or knows someone who has do you have any advise I could pass on to him? He's had nonstop chronic pain for 2 years solid and I'm worried about him being on these pills. He's had to detox from vicadin before and it was rough for him. I don't want to see him end up a pill popping junkie. Or becoming so addicted to them that his pain becomes worse than it actually is because his body needs the fix.

Thank you for any help you can provide on this.