I don’t know much about healing a finger, but I have experience with wounds.
I had some abdominal surgeries this past year and the second one was open, which means that the incision went from just above my pubic area to about an inch above my belly button. There was a drain placed in the bottom part for the first 24 hours after surgery and when it was removed it left what I can only describe as a big gaping hole – very disconcerting. The rest was stapled shut for 14 days, which is what is recommended. Now I had an awful time with my appetite and with nausea after this surgery, so for several weeks I was not getting proper nutrition. This meant that my body had not done enough healing in the meantime to close up the wound, and when the staples came out, it came open up to my belly button. So that – nutrition – is a huge factor.
The wound was maybe 4 inches long and 2 inches wide and half an inch deep. Wounds like that have to heal from the inside out, otherwise you can end up with pockets of fluid trapped which will cause you problems down the road. So you pack it with wet gauze and a dry dressing on top to wick the drainage out.
Over, let’s see, the course of 4 months, I managed to get the wound smaller but it still wasn’t anywhere near gone. I was still having a lot of trouble with eating for about the first 2 months of that. Just when it would start to get better it would get infected – I had MRSA twice, it’s damn near impossible to avoid – and it would get bigger again. Finally it got designated a chronic wound because it seemed like my body was not capable of healing it (in the midst of healing up from surgery, was way too skinny, just not in good general health). Luckily after 4 months it was time for my third surgery and while I was under the surgeon went in and pulled the sides of the wound closer together. I was finally able to heal it closed within about 2 months aftert he did that. I have a hell of a scar now.
Hope any of this info is helpful.