Well, I don't have any peach trees here. But I do have lots of other kinds including mango and papaya. When I have a tree that bends or splits, I do support them but I put the cord or support rope through a length of old garden hose so it won't cut into the tree. You have sap coming out the wound. That's not as dangerous as you may think. It is one way the trees heal, just like if you cut yourself. If it eally bothers you too much, you can buy a type of tar or wound dressing for trees. I don't think you've killed it. Give it some TLC and see how it looks in spring. You may be surpprised.