If I understood correctly, you'Re trying to get which button was clicked last to store it's name somewhere. You could use the Tag Property of your forms component, a property which is unseeable by the user and exists on most Windows.Forms components. If I'm not mistaken, it's type is object, so you can put anything.
Another way to do that would be to use the (object sender) part of the parameters in the event to get the sender's name like this
invisLabel.Text = (sender as Button).Name
In that strip of code, invisLabel is a label in your form which's value is your button's name. The part in parenthesis tells the compiler that the sender (your button) is a Button, so you can get it's properties there.