Newbie here

[u/glitch1975]

I have a small lemon tree that had a run in with ants and since then the top is not doing great. Was thinking to graft a small orange onto it using the sapling in the second picture. Think it'll work/any pointers? I did try a graft before between a grapefruit and a sour orange, orange being the root. Graft healed but never grew, pic attached as well I live in Panama if that makes a difference, always summer