Anyone know what this rash on my baby is?!

My baby is 7 months old and he’s had it for 4 days. I took him to the doctor and the doctor said “it’s hard to say”

She says she thinks it’s either a virus or allergies and to call back if it’s still there in a week...

I really want to fix it ASAP, he finds it a little itchy, I mean should I get a second opinion from a new doc??? Any ideas