idk what this issasss omg

Okay so I woke up this morning and down there kind of itched and hurt and when I took a shower I looked and it looks almost like a blister (like those little clear blisters that people get) except this one is big and hurts. Is it just a blister or could it be like an std or what bc I'm like freaking out and I don't like going to doctors?!?!?!? Someone pleaseeeeee helpppp 😭