Guitar Super System

So I just spent the last three months unable to play my guitar due to a work injury (almost cut my finger off) and so now that all the pins are out of my middle finger and the bone is healed I can try to get back on the horse with my guitar journey. I was wondering if anyone here had any tips or exercises I could use to help me build back up the dexterity I used to have because as of now I’m struggling especially with the finger still slightly swollen and not having feeling in most of the tip of my finger.

I've never had to deal with a finger injury, but I did have a shoulder surgery early in my guitar playing journey. My advice would be to make sure you let that finger heal up as much as possible. I ended up creating some bad posture habits that I had to retrain later down the road. I'm not sure if the injury is on your fretting hand or strum/picking hand, but either way, the usage of that finger is important and you don't want to push it too early and create a bad habit.
You also may want to think about your guitar's setup. Maybe you should go down a string gauge. Or maybe the action needs to go down some. Think about your deficiencies and then try to help minimize those with an optimal setup.
Once you are healed, then start back like you did in the beginning. Do some dexterity drills. You'll need to exercise the hand muscles to build that strength back up. Repetition, repetition, and more repetition. It may take longer than it should given your injury, but that's understandable. Just stick with it and you'll be even better than before.

Active recovery in rehab is the trick. Injuries are like water on an un-anodized metal hinge. If you let it sit and don't work the hinge, it'll rust and freeze up. You have to stretch, protect, and gradually work your way into playing at 100%, but you absolutely CANNOT overwork it too early, or let it sit and do nothing with it. Even beyond guitar playing, you want full neurological and circulatory function with that digit or like....everything in your life will have to be worked around a finger that isn't 100%.

I hope you are well on the path to full recovery. Take care of that finger, man.

Love---Your neighborhood PA in training

Take your time, listen to your body, and be consistent in your rehab. I wish you well, my friend, you'll be back!

-Tyler

Easy answer play. There are many finger/hand exercises on the web. I lost my left hand (fretting hand) index finger (first joint) between a chain and sprocket at 24. I stopped playing and was frustrated with having to build calluses and raising a family and other interests got in the way.
At 67 I began again, now 2 yrs in. I had intuitive knowledge having played before. I tried all kinds of finger extensions and finally went au naturel. You'll adapt if you need to. Jerry Garcia cut his fingers off axing a squirrel. Reinhart is another. Tommy Iomi another. The real question is how much do you want to play. I did a deep dive on the internet to find something I thought would work and used finger tip cushions and other prosthetic things etc. Not now. You'll find something. I play lead mostly. Good Luck!