Please tell me is parosmia is dangerous?

Possibly: Parosmia characterized by the inability of the brain to properly identify an odor’s “natural” smell, and instead interprets it as burning, smoking etc. It can be a symptom of epilepsy, result from head trauma, and can be seen in parkinson's. See a neurologist if you think you have this.

Not usually: The sensation that things do not smell as they should, all toward bad/noxious smells instead, by itself is not dangerous--and it does tend to improve over time (years).