This happened a few months ago while I was doing some precision grinding with my angle grinder. When it happened I felt it right away but still had the grinder running and couldn't drop it. I had to shut it off and put it down safely, instead of throwing it aside. Then quickly go and clean all the crap out before the pain started. I contemplated going to see the doc but opted not to. I was concerned that it might not heal well since there was a bit of flesh missing and the white thing in the cut looked like it might be a nerve that could end up healing itself to the skin and that might be a long term issue with sensitivity. In the end it turned out fine although there is some sensitivity when it gets cold.