You may have used too many things on it, and have have caused a reaction from that.
Alcohol is very drying, as is Abreva and cortisone.
In any case, itching and redness is not herpes, nor is a patch rash. That sounds like an allergy or dermatitis. Cortisone would help both. Herpes doesn't react well at all to cortisone, which is a steroidal cream.
Try just using the cortisone and see what happens, or don't use anything, and let the doctor see it and see what he thinks.
The blood test may be negative if they did an IgG because it can take up to 4 months to show positive. If they did an IgM test, it's terribly unreliable and shouldn't be done on anyone but newborns.
That all said, it doesn't sound like herpes to me, but let your doctor see.