Your dog busted a bloodvessel in the “flippyflap” part of the left ear.
We can “leave it alone' and itll bust open all the way, or resorb and crinkle like a pringle and a ruffle had a baby.
Some people used to just pop the thing with a jacknife and send em out into the yard to clot and that works, too. Gotta keep 'em from shaking their heads so they don't bleed again / more. But they can't really bleed to death so it was a pragmatic, 1940's and messy way to fix these
We can tape overhead and drain it with Kenalog infusion and that's a great way to do it with less mess, pain and better (less] crinkling.
I think the other dog mighta broken that vessel. The ear isn't infected at the moment.
The ear can be incised with a long, linear incision and then the flippyflap embroidered / quilted together with multiple little sutures. This is very profitable. It is arguably overkill.
I think if it was a show dog and you wanted the best chances of “healing without a trace”!
My favorite is tape and drain.