Part of the show Science of Sex, Smell and Pheromones...
I lost my sense of smell. Can I get it back again?
There are various ways in which you can lose sense of smell. For instance, people can lose their sense of smell if they are allergic to something. These people can often regain it if the object they are allergic to is removed. In other people, events such as car accidents can cause a person to lose certain connections in their brains and stop being able to smell. It can sometimes come back after long period of time, but this usually depends on the type of accident the person was involved in.