You can edit as much as you can I believe, but just until the voting starts. When voting begins, you can't edit. 

I think the chin area could do with some darker colours too as it seems very boring right now

thanks, I found it really hard to get the feeling of rust from the snes palette even though it has a few orange and brown colours. If I were to re-colour it can I submit it again as an edit for the weekly challenge? 

That orange feels a little saturated, but the textures are nice, especially the hair.