@luckow I suspect that the ends are rough, and trimming trimmed them so as not to be rough, and thus, not causing itchyness. That is my guess in my own case, that when I let it grow longer without good beard oil that the ends were always rough; trimming didn't help because the beard hair had spent all that time growing rough, too (without good beard oil). Once I started over and used good beard oil, it stayed "healthy" and not rough tipped. So, in addition to your 4mm trim, be sure to keep it clean and use good beard oil (not beard moisturizer). Keep us updated!
