Yeah, they can - Wylie had a big 'ol "thang" under his chin - pretty close to his lip - and it was pretty big (about 1.5 years ago) and I freaked out! Took him in, doctor said they can pimples - but he actually said Wylie's was a either a little cyst or a little wart (ew) - and said to just watch it. He said it would probably just go down on its own and if it didn't, it could be removed.
You could put aloe on it, hydrocortisone cream, and/or antibiotic cream (which would be good esp. if she itches the area, as it would prevent infection if she breaks the skin).
