Hi, I'm A 16 Year Old Girl And I Have

Hi, I'm a 16 year old girl and I have a rash on my chest and I don't know what it is. It's like small red dots, but occasionally they are sort of like a pimple, like if I squeeze some they pop. They are mostly on my chest and stomach but there are some on my back and very little on my arms and legs.
It's not severe, like when I look in the mirror from 3 feet away I look perfectly fine, but up close it's clear that something is strange.
I am prescribed to Lexapro and Vyvanse but I've been taking them for a long time so I don't think it's that. I haven't been using any new lotions, perfumes, soaps, or products
I have clinical anxiety and I've heard if people undergo a lot of stress you can break out in hives. I just want to know if it's my anxiety or something else, and what to do.
I'll be going to a doctor within the next couple of weeks, I just want a quick answer if I should act fast or something. Thanks!