Discharge causing rash?!

So today I was wearing undies of course and I'm not on my period and not due for it until two weeks from now and my discharge is really heavy. My underwear is/was soaked. I put on a liner and now I have this rash type thing on the crease of my left leg. It burns really bad and is red. It is starting to come up on my other leg and it hurts to wear underwear.