You can still push the button and it'll work. It feels strange at first, but it should still last for another year or two. I lost my "L" key and just made due until about a month ago. You never realize how often you use the "L" key until you lose it lol
And then when the little rubber nipple (it's the only fitting description I can think of) runs away, you can still use it, but you have to put your finger directly above the key.
(and the key here is not to lose control)
(and the key here is not to lose control)