4 months ago I started getting severe itching on my vulva. It was so intense that when I would scratch it was very painful like if you had a blister and scratched it. I have tried many, many creams and ointments with very temporary relief. I have never had anything like this before.

If you have not, it's time to visit your doctor for a proper diagnosis and treatment.

Here is a good website that covers many reasons for vaginal itching, or itching in the general area. But it is really isn't an answer and as J_9 mentioned, best bet is to see your doctor.

Vaginal itching: MedlinePlus Medical Encyclopedia

To the doctor you go. We can guess like you did, but that didn't work out so well for you. So go to your doctor and find out what's really going on, and get the proper treatment.