Is there a good way to unmerge verts without undo

I was merging a series of vertices because I did not have auto merge on. Along the way I accidentally grabbed an unwanted vertex and did not notice. 30 some odd steps later I was looking over my model and saw that I had done this. It is to far back in my history to undo. What is the best way to fix this.

I’m a noob.

Also I’m sorry if this post is in some way in appropriately done. Like I said I’m a noob.

Mesh / Vertices / Split to separate the selected vertices but do not create a new object from them
Mesh / Vertices / Separate to separate the selected vertices and create a new object from them

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Rip vertices/edges https://www.blender.org/manual/modeling/meshes/editing/vertices.html#separating
Edge split https://www.blender.org/manual/modeling/meshes/editing/edges.html#edge-split