Skin color turned inverted!

Hi,
I'll make this rather short.
I booted up Minecraft and saw my skin turned into this* (*see attachment named "SkinBug" Normal skin is "Skin") The only thing I could think of that could've been the reason behind this glitch is 3D mode. I had 3D turned on when I booted MC.

I can't remember what I did to fix it. Sorry. If I remember I'll comment.

Tell me if there's more information that I need to give