Something you could try is logging off for 15 minutes and trying again after, as after that period of time a quest location will do a soft reset. If that doesn't work, you will most likely need to abandon the quest. You shouldn't have to get the bite again though, as I think that's good for a few days (check your Active Effects for Sanies Lupinus). What you should be able to do is just get the quest again from wherever you got it before.