No... You just have to have the traits, skills etc they're looking for. They won't care if you're 'ugly' (which by the way, doesn't exist) you just need to be able to work with customers and stuff.
It would be extremely shallow of the employers if they turned you down for being ugly.
Adding to Courtney's answer: you do have to have good hygiene and dress appropriately though.
It doesn't matter you just need as good attitude.