The only thing I can think of that would cause irritation is using a tampon and removing it when you are dry. Sometimes using a little lubricant on the tip of the tampon can help if that is the issue.
I went to the tampax website and there is a feature there called Ask Iris. You should send in your question and see what she says. (I would have done it myself but it asks for your age and you didn't include that information in your post.)
Good luck in resolving your problem.

It could be an allergic reaction...

you may have to use pads for a while until you find the cause of the problem

sounds to me like you are getting a yeast infection. I would get them after or during my periods before. I asked my doc about it and he told me to stop using scented tampons and it should stop it. I did and it hasn't happened since.

Research toxic shock syndrome.