Untreated......it doesn't clear up. At first a small scab will form, picked off, will reform again and gradually get bigger over the months. After a time, an ulcer will form which will get infected, smell and expose bare bone.
Pain will be prominent....severe pain.
The you will develop swellings in other parts of the body (lymph nodes) and these will break down and produce smelly ulcers.
You will get thinner, the pain will get worse and you will eventually die.
I would not advice going down that route.
If treated at the Bowen's stage, the above will not happen to you and depending upon the treatment it will clear in a matter of weeks.