Is this a tick on my dog?

I can't tell if this is a tick on my dog or not. It's been there for awhile- I just thought it was a blood blister. If she licks it or bites it, it pops and bleeds a whole lot. It's on her stomach. But I can't tell if it's a tick or just a mole-like sac filled with blood. Do ticks bleed when touched?