My best mate is a mechanic and does this occasionally when hes trapped his finger in an engine.
I did something similar to my husbands nail when he trapped it between some rock and an iron pipe. I used my nail piecing drill to release the puss under the nail. He went to the minor injuries unit 2 days later to have it done again, they did it closer to the cuticle than I did. They used a cauterising tool which left 3 blackened holes, mine was a clean smaller hole.
I wouldn't do it to a client and having discovered our local minor injuries unit i'd send husband there if it happened again, but needs must when i did it (late at night causing him pain but didn't warrant a visit to an over stretched A&E)