Hi. My Name Is Robin (45 Year Old Healthy Female).

Hi. My name is Robin (45 year old healthy female). I started getting a red bumpy rash on my arms two days ago and now it has spread to my torso. They don't really itch. I have no other symptoms. I've eaten nothing new, used any new soaps, lotions, taken any new medications, etc. I've been taking Benedryl and it doesn't really seem to do a whole lot. Should I see my dermatologist, or wait a few more days? I've read where there are viruses that just run their courses without any intervention. Thank you.