I would suggest a vet if it continues. Birds will get hoarse brom time to time but if it lasts any longer than a day it could be a sinus infection or sarynx, pharynx or larynx (they are a lot more complicated than us LOL!) It would also depend on if your lovebird is hoarse on everything she/he chirps or says or if it is more of an imitateable sound (such as we have several birds with bad coughs for attention they have learned to sound like an old choking man LOL)