Possible, they just do not clear up overnite, it takes longer than the time she hasn't smoked, years.
She should really see a doctor, she may have some respiratory infection, not necessarily from pot but infections, allergies, gee, all sorts of things can be the cause of this.
Pot though, I would not suggest using it any longer, there are other healthy ways of having fun, and/or relaxing.
I just think she needs to see a doctor, find out what is wrong and then follow through with whatever treatment her physician prescribes.
Hope she'll be okay soon.
Take care now,
DE

In giving advice seek to help, not please your friend
SOLON