Irritation or STD???

So a week ago, I hooked up with a guy bigger than I'm used to. (Condoms were definitely used) He went a little fast through foreplay so I wasn't as ready as I should have been... Long story short, I'm pretty sure he tore something...

I have been a little sore since then but most recently, I noticed some irritation along the outside of my vagina after shaving. It's not blistery, just red and inflamed...? Not sure how to describe it.

So could the irritation be from shaving too hard, healing from the tearing, or could he have given me an STD?? I'm very paranoid about all of this stuff. Please help