bad technique

Hey, has anybody been through this? After years of playing I've decided that I'm not gonna move any further. At certain speeds the tension of some of my left hand muscles was too high and it no longer could be called some individual technique. Is been already months and hundreds of yt movies...

Title, I knew my skill level would deplete, but I really do suck a lot now and it's very surprising to me (and, I admit, funny). This is the first time this has happened to me, I even got a blister on my finger lol. I just shake my head in disgust whilst playing at how terrible I am. Anyone...