I once crushed my finger when I was around 16 working on my truck at the time (crushed it between the frame and a breaker bar). It swelled pretty bad but later went down in size. Over the next few years my finger got larger and larger in diameter. I finally saw a dr. who sent me to a specialist and he determined that the "shock" caused to my finger caused a fibrous mass to grow in my finger. As a result, I had to get surgery on my finger, the mass had grown around some nerves so they had to cut those out as well, and then put somewhere around 30 stitches from my knuckle to the tip. In the end, the mass was removed but I still can't straighten my finger all the way and I also don't have feeling in it. Regardless, I still love to work on cars when I have a chance