First, I can't really help with the mask as I've never done that sort of intricate molding, but there is a woman who did an Ood costume from scratch who may have suggestions.
Second, if a mod sees this, it should be in the Doctor Who section of this board. It might get seen by the correct people there.
Cons 2013/2014 - Ecto Con | Chicago TARDIS | Ahn!Con | Kawa Kon | Wizard World St. Louis | Costume-Con | Marcon | Cosplacon | Dragon*Con | Archon
In Progress- Cecil from Welcome to Night Vale
| Jonathan Strange from Jonathan Strange & Mr Norrell
| Madeline Westen from Burn Notice
Misha's Costumes in Progress- Mr Norrell from Jonathan Strange & Mr Norrell
Ecto Con: St. Louis's Ghostbusters Convention!
Kawa Kon: Into Darkness in 2014!