I need to manipulate the vertex of a skinned mesh, but not its sharedMesh (beacuse it remain deformed also when i stop the game). How i can do?
Copy the mesh on startup, so that you're operating on the clone instead:
void Start() {
Mesh oldMesh = GetComponent<SkinnedMeshRenderer>().sharedMesh;
Mesh newMesh = (Mesh)Object.Instantiate(oldMesh);
GetComponent<SkinnedMeshRenderer>().sharedMesh = newMesh;
}