Please don't think I'm trying to preach, or instill poor safety practice. I haven't climbed for a living for over 20 years now. Safety has come along ways. The only problem with things like chain brakes is they set you up to use poor safety techniques. We didn't have brakes so you never let a saw hang while running. Now it's common practice to let the saw hang while running, just put the brake on. I have never met a climber that wears chaps up a tree and helmets were a major issue, no one wanted to wear them. Safety practice is more important than safety devices. Safety devices cover the lapses in safety practice.
I had 2 cuts that safety equipment would have prevented, but safety practice would have prevented them too. The first was when I was about 16 or 18 years old. I picked my leg up to step over a log and stuck it into a moving chain. The chain was too loose and the idle too high. My cut looked a lot worse than the OP's.
The other was late in the day, my hands were numb from cutting saw logs all day. I had my thumb above the handle wiggling my fingers when the tip of my Super 1050 hit a log on the far side and kicked back nicking 3 fingers on my left hand.
Funny how the stuff we live through we eventually brag about. How many times have you had a prunning saw break through and hit you in the knee. I actually had one stick in my knee cap once and was showing the guys on the ground that it wouldnt fall out, I had to pull it out. The next day that knee would hardly move.
Well, everyone be carefull and work safe, Joe.