LSR - any chance to repair?

[Evil Homer]

Hello,

I cracked one of my LSR tuners.
I tried to open the string-lock, but I wound in the wrong direction. Now it's overwound and no matter in which direction I wind, there's no screw thread. So, the string-lock doesn't open anymore.

Is there any chance to repair this LSR tuner?

When I look from the top into the tuner button, I can see a screw nut. Is this nut for unlocking the string?

[Evil Homer]

Now I found the problem: The screw head is torn off.
A precision mechanic should be able to get the rest of the screw out of the thread...

However, is this a common screw I can replace? Or is it a special LSR-screw?