Vaginal pain

So basically three days ago my vagina around the opening started to burn and feel really sore just really bad excruciating pain. But then my period started and that kinda soothed it? It still hurts but only if it’s even remotely dry and my period is unnaturally light rn? I’m not sexually active so it’s not an std or sti and I don’t think it’s a yeast infection(at least I hope not). Help?