I've used Dean's scalloped belly patches to repair chrysals and hinges before. You've got to make them right for them to work. (I learned the hard way.) They need to taper gentley into the limbs. If the taper is too abrupt, the patch will be prone to lifting, starting at either end of the patch. Also, use Urac to glue them in and only use a VERY light clamping pressure, just the minimum to hold it in place. I got that tip straight from Dean. These things don't seem to work as well with a razor thin Urac glue line.
In any case, that chrysal looks bad. It's deep and right at a bad knot. I don't know that a belly patch would save it. Especially since there are alot of other crysals forming, I'd hang it up or if you can stomach it, just use it for kindling. I'm not big on dicey fixes or just shooting bows till they blow up. (I can't believe people actually do the latter. I have an aversion to loud bangs in my face, painful smacks, and spilling blood.)