What kind of paint did you use? Has the mask been completely repainted?
I think theyre dark enough, you just need to do a thin line of grey paint out-lining the top lip.
hey hey now that’s a famous mask that’s ol bluelips! 
You can always draw out the shape of the lips you want on paper and either scotch tape over it a few times to make it rigid like a stencil or cut it out of plastic and air brush it on. That way you get the fine lines but not a definite line. Hope this helps