My dad suffered a spontaneous bleed from his privates. The bleeding was stopped. We did not identify a lesion on the scrotum. The only indication was a very small pin hole area. The testicles were normal.
Melanoma on the genitalia is very rare but other forms of skin cancer such as squamous cell carcinoma may be seen. It would be a good idea to have the area checked by a dermatologist and if necessary, a biopsy will be done. There are a lot of things that can cause the symptoms that you have described and it may be something minor.