The leaf damage is peach leaf curl and usually happens if the leaves get damp at the wrong time. Locally we grow the peach under the eves of the house so that it never gets rained on and are careful not to
water the leaves.
The trunk looks to be within normal range with a lot of sap leaking from the cut. It was probably cut during the growing season or when the sap was running. (think maple syrup). It
should seal itself if you just leave it. To prevent this in the future try not to make such a big cut if you can avoid it or use a wax sealant to help protect the wound.
There might be something else in the black part of the bark, but it's difficult to see and depends a lot on your location and what kind of space the tree is growing in.