I have a rash on my scrotum appeared after i washed my genitals with a bar of soap in the shower. is it dangerous?

If so, stop...: It seemed you have figured out what has caused your scrotal rash; congratulation!. So, you may have self-limiting contact dermatitis and logically, just stop its use. To some, obsessive chemical and physical cleansing inflicts unnecessary suffering. There's no cure for it, but use common sense to avoid it and apply topical steroid cream thinly will shorten the suffering from this kind of rashes.