Back of hand swelled up during dips

[jonworkout2]

I was doing dips which I have done Thousands of times before.
Last time though I got a really bad pain in the back of my hand and had to cut my workout short.
A few mins later I look down at the back of my hand and it had swelled up.
I iced it and although it is still a little swelled a few days later I don’t feel any pain and I can use it as usual.
I went to see a hand specialist who had no idea what the problem was and says I should get a mri if I want him to find out what the issue is.
I dont really want to pay another $300 for a mri especially as he had no idea to begin with what the issue is and it was not cheap paying him out of pocket.
Has anyone else had a similar experience and what was the cause of it?
Thanks in advance
Jon