Sage and Finn

In season 3 Sage has a thing with Finn which didn't have a lot of time to develop on screen because it was just a means to further the storyline but when Matt stakes him, Sage leans over him crying.. Why didn't she just remove the stake herself?

It wasn't a White Oak stake was it? Or is there was a thing that said a Vampire can't touch the stake right?

Just looking for clarification.