Tinea cruris (jock itch) symptoms do not suggest herpes; a red rash and itching of the scrotum and in the crease between leg and genitals are the most comomn sites, just like you describe. Herpes doesn't occur there. When herpes causes symptoms, it results in blister like sores that you could expect to see on the penis, immediately above the condom coverage--and probably nowhere else. It does not cause a diffuse red rash.
Anyway, the chance of getting herpes from any single encounter is very low; and drops to virtually zero with a condom. Although herpes can occasionally be transmitted by skin contact above a condom's coverage, it is rare.
There are conflicting research results, but most likely HSV-1 makes people more resistant to HSV-2 if exposed. However, any protection is not very great. People with HSV-1 tend to get less severe symptomatic outbreaks when they catch HSV-2. But the nature of those symptoms--i.e., what the lesions look like, their location, etc--does not change.
You should put herpes out of your mind and not seek HSV testing on the basis of this exposure. You can try OTC treatment for your possible jock itch; it will be in the same area of the pharmacy as the athletes foot creams. If that doesn't clear up your rash, see a health care provider.
Please do not follow up with "yes, but?" and "what if?" questions. Unless you develop more typical herpes symptoms, there is no information you can add that will change my advice.
Good luck-- HHH, MD
HHH, MD