Hops, I'm just now on scene of this wreck.
Doc CC had a clever retort which could be your answer and Dan had some good points too (that hurt to say).
I would think that any dermal surgery would not get into the nerve pathways which are mostly protected by/under muscle tissue. The exception would be when crossing bony joints and yes the ulnar nerve is fully exposed here (funny bone). The radial and ulner nerves are the 2 main nerve roots and they arise via C5-T1. At the shoulder the normal pathway is deep within the axilla region. For all you lay types that would be the arm pit. They seem to run thru the anterior shoulder more.
The ulnar is the one that innervates the motor and sensory little finger while the 4th finger gets some from both the ulnar and radial nerves.. I feel safe in saying that the surgeon missed your nerve pathways with his knife. This leaves us with the question of what the heck happened .
I think we can rule out AIDS and COVID-19 for the most parts. Which leads us to Doc CC's thoughts. I'm grateful that this set of thoughts was organized and seemed on point which has been slipping as of late. Positioning while doing surgery. Did they use a general anesthesia. Doesn't seem likely they did a nerve block but maybe. Either way they can move and manipulate your arm and shoulder in ways that you wouldn't normally do while pain is absent to prevent these movements and could have stressed the nerves or even entrapped them in some way.
My recommendations is rest of the affected appendage. No stress movements. On your follow up at the office tell them the effed your arm up and ask the WTH?
On a side note when I had the big 6'5" patient that was getting a bit loud and starting to act out in the ICU while I had him sitting outside his room where I could watch his olde azz . Per the doc at the time said I should give him a sedative to "calm" him. I think I gave him Haldol via IM injection. It knocked his d1(k in the dirt . . . FAST. I needed to get him back in bed before he fell out of the chair. Got him back to the edge of the bed by dragging the chair, stood him up to pivot him into bed and he collapsed onto the top of me. I had to feed sack his beeg ol butt onto the bed and in the process tore my inguinal regions.
Didn't notice the injury at the time but over the weekend I ached "down there". I rested Sunday, the pain went away, I went to work on Monday and started hurting mid morning. I went down and caught the trauma surgeon in the Medical ICU, told him my plight, at which time we went into an exam room (the bathroom) where I did the turn my head and cough thingy. Had repair surgery on Wednesday. Yeah, they put in a floor mesh.
I tell you all this to say . . . I still can't feel my left nutt. Been 3 years. Sometimes nerves don't reconnect if they've been cut.
Had my whole right hand loose strength after a weekend of crawling around laying laminate flooring. It would just fold up trying to put my hand in my pocket. No pain and no numbness. 3 days rest per the neurosurgeon and I've been great ever since. Rest can help if you've just stressed a nerve.