std? or rash? freaking out

so I recently bought a dildo, i washed it, I used it with a condom and I my vagina started itching and burning and had little bumps on it. I assumed it was a rash from the dildo so I stopped using it. I did have sex with someone about a week before I used the dildo. could it be an STD from him? or is likely the rash? it's gotten worse bc I've stupidly hooked up 2 days ago and had sex, I did mention it to the man before we had sex. Should I schedule a doctors appointment? Or try creams and other things first?