Slightly concerned- bump on lip

Hello,
My sweet little girl Reba has a new bump on her lip (or rather, just below.) She's generally pretty healthy, and she is still her normal half angelic/half insane self.
She did just have fleas less than a week ago, so maybe it is a reaction to that? She also eats anything she can find (like lots of human food).
Pic below! Thank you!

She is a beautiful girl. Anyway you can get her looked at by a vet?  

Is it the reddened area on her lower lip in the photo? I can't quite tell.

Could be from the fleas, some cats react like that. Another thing that comes to mind is acne- one of my boys breaks out if I use plastic bowls.