I have had this problem twice before myself, with FLATWOUNDS. I just got another this morning and googled it to see if anyone else has had this problem. Having worked in paint and body shops for 27 years I have had hundreds of metal “splinters” from swarf or the grinder. And the ones off super fine steel wool are really painful and painfully small. You can’t see them but they normally work their way out. Don’t dig around in your skin because you will make it worse. Being heavy handed on bends as a beginner was how I got the first one but that was a long time ago. Looking on the web for advice, because although I have never heard of anyone else having this problem, I have seen people play with a gloved hand?? There seems to be a lot of gibberish, people being rude to each other about ghost splinters and nerve damage and the likes. 😳SAD😳I have only personally had this problem with the cheaper flat wounds on bass, my guitar had never hurt me 😂
