looks like the piston lives another day.
Rings break. Yours is not the first, nor will it be the last.
I suspect a small piece of the broken ring, or maybe foreign matter from the exhaust to have caused the damage on top of the ring groove. Since gas pressure or momentum tend to press the ring down all the time, this will not impair operation.
Check the ring groove bottom for damage. The old broken ring is a good tool. Fit a new ring and you will be fine. Use more oil for the first gallon (~4%), and go easy on the throttle until things have seated again.