Itchy scrotum for three months, no redness or rash. unprotected oral sex around that time, but was recently tested for stds and tested negative?

Scrotal itching: Common non-STD causes of scrotal itching include eczema, psoriasis, jock itch (tinea cruris), candida (fungal) infection. If you have any eczema and psoriasis lesions in your body elsewhere then this may be the culprit in your scrotum as well. Otherwise, it is best to maintain good scrotal hygeine and keep the area dry. If the itching does not resolve in 2-3 days, then I recommend a physician eval

Jock itch?: An itchy scrotum is not a symptom of STD. It's most likely jock itch, which is a fungal skin condition. You can get an antifungal cream or spray without a prescription. If symptoms persist after using that for a week, then see a doctor. And please stop having risky sex.