I accidentally deleted a vertex So I'm relatively new to blender, and I've been following a tutorial to get started. I'm at a part of the tutorial creating a mug, but I accidentally deleted one vertex on the lip on the mug: (which, oddly enough, can be seen in edit mode but there is no hole in object mode:) and didn't realise 'til later, so I can't simply undo back to before I deleted it. I have no clue how to put it back. help?
.. Loads of ways to do it.. but one option..

Assuming your mug is circular, Z-up..

Set Pivot to '3D Cursor' and Snap to 'Active', 'Vertex', affecting rotation




Select a good circle in your mug, which will yield its XY center
ShiftS > 'Cursor To Selected'





Select a region of faces you can copy to patch the hole
In Vertex Mode, select a suitable vertex to snap to, and make it active





ShiftDRZ duplicate and rotate the patch, and snap it into place.




After AltM merge > 'By Proximity'.. repair done.