I had something different from you, but my grip strength was in bad shape for a long time.
Flexor-Tendon Grafts on 2 Fingers right hand in 1975 ... the injury was a result of an attempted carjacking.
One of the bad guys had a knife. I grabbed it and disarmed him rather than letting him stab and possibly kill me ... but unlike a Hollywood movie knife attacks leave scars.
Before this I lifted weights 6 days a week, so I was very depressed and unsure of my future doing things I loved.
My hand was frozen with not much movement ...the Doctor was a head of his time. He did a great job and once he gave me the green light to work out again, I took my time.
My strength came back and about 90% of the movement in my fingers ... I was able to pull a 600-pound deadlift and bench press 485 pounds 10 years after the surgery.
Worked 25 years in Corrections City Jail to Supermax prison had many uses of force incidents using my right hand over the years ... this past Thursday I turned 70 years old and did a 315-pound bench press and pulled a 365-pound deadlift. Don't feel sorry for yourself, fight with everything you have to get back to where you were before this happened to you ...
If you need help once they tell you can do stuff to strengthen your hand, I would be glad to share what worked for me.