Psoriasis on the scrotum or herpes? :(

Hello. I have psoriasis on the scalp and other areas but have never experienced it (in a private area). I had protected vaginal sex, unprotected oral with a woman around a month ago (she had no visible signs of an std). I have what I'm hoping is just a small outbreak of psoriasis on my scrotum, I just noticed it a few days ago, but it may have been there longer (on underside). Can you distinguish the differences between a herpes (HSV) infection and what psoriasis may look like on the scrotum? I am rather embarrassed and worried. I'm really scared, especially after looking for photos online, its hard to tell the two apart, especially in mild hsv cases. I'd really appreciate an experts opinion.

Thanks. -S