Be wary of filters
What it largely seems like you've done, not just with this piece but with several of your pieces, is whipped something together fairly quickly, then decided you didnt quite like it, so you ran a photoshop filter over it.
You want to be showing off your skills as an artist, not what photoshop can manipulate. My advice would be to just keep working using only the pen tool, and to practice making art without ANY photoshop effects or filters.
once you get comfortable with that, try applying different textures SPARINGLY, usually to only small parts of a picture at a time. Tutorials are your friend~ they'll help show you how to correctly and effectively use a lot of the different filters