I did exact same thing trying to treat a small hemorrhoid and the itching . I didn't know I should dilute it and have a nasty burn and in so much pain. What did you ever do to feel better? I'm sorry this happened to you. It's awful!
Just wanted to check in and see how you were doing? Hope you are healing up and feel better!
I would stop using the vinegar and witch hazel now- you want to keep the area clean if there is an irritation, but you can use a mild cleanser. See how you do with just stopping the treatment- as far as if you think you have a hemorrhoid or skin tag- get to a doctor for the best treatment for those, since at home remedies have irritated the area.