Sometimes they can go a bit stale, but I have never heard of them going bad. They do have a life span due to the fact that they contain spf15, but I noticed that mine doesn't have a exp date on it, sooooo to make my long story even longer....I dunno? Sorry
Look for a date.If you got it shelved in September it should be fine unless it's 100% organic wich it's not so the smell may be radiating off mixed lipstick,if you wore it over something that had scent on it.If you shared it with someone.Never share your lipbalm! btw.If your not comfortable with the smell what can I say but trash it.Thats what I would do.As for it going bad I highly doubt it.
You know, I used to have a tube of regular lip conditioner, and it went bad within like six months. However, my tinted lip conditioner pots haven't gone bad, and I've had one of them for like two years.
I would be very wary of putting anything on my face that smelled really bad and that smell wasn't there before.
Good for you for contacting the company. They can look at the product and see if something went wrong in the manufacturing process. You may have just saved many people from the same problem.