raised parotid glands?

I recently "discovered" my parotid glands as flat, blue-ish/purple-ish patches next to my molars on both sides of my mouth. I wasn't sure what they were at first and became very paranoid immediately, and having read that mouth cancer lesions will bleed when scratched, I tried scratching them. No bleeding but they've been slightly raised ever since. They don't hurt, haven't affected my ability to open my mouth or anything like that, but I've been paranoid lately. I'm seeing my dentist in about 10 days. Is this a common thing, for the glands to become slightly raised like that?