Welcome, Pat!
What kind of Cassia tree is it, and about where in the States are you? The species and the local weather will affect the answers.

I don't know what kind of Cassia tree it is. I live in Central florida on the east coast. Zone 9

Ah! Like my zone (sort of). A light dose of rose food will probably help it to come out faster. I would also inspect the base of the trunk. In some of the more severe frosts, a layer of cold air near the ground can kill the bark at the base, eventually killing the tree no matter what you do. Symptoms include cracking, loose, and/or oozing bark. If that's the case, and more than 1/2 of the circumference of the trunk seems to be damaged, you may need to replace the tree. Good luck on that!