Just today I noticed a light red rash on my neck with a few spots that extended down my arm. It is painless and relatively hard to notice, but it still freaked me out given my recent experiences. It could be an allergy or an irritation, but it still freaked me out as I say. Is there anyway to know whether this is related to an STD? My sense is that STD rashes are more pronounced than this, but I thought I would ask.