it's a nice piece of drawing and the band thinks so but:
-if they don't want it for them then they don't want it. (i think they are seeing Helllraiser or some stuff instead of what is there: braces. And they can't get around their first impression. Oh well. But we all know that these things are for bands and if the band don't think it's 'them' then that's that, pretty much, right?
-second: i have found that bands are often have really uncreative ideas about their own image. realllllly boring and safe ideas often come from the most 'edgy' band types. Show them this same exact thing in pink and yellow and green and see how they think. Perhaps they would like yet another flaming skull or a hammer with lipstick or or or
the best thing to do is say 'oh well' and go have some coffee.
bands mostly never get to say anything about all these posters we do and can be happy or sad or ambivalent about the result when they show up to gig and see it, so when they DO get to say yes or no, then you have to just abide and not complain too loudly outside your head.