What Causes Irritated Lump On The Vaginal Lip?

It feels like I have a cut/hair bump or some type of irritation in the crease of my thigh area connecting to the private area or it may actually be on mu vulva lip. I can't really see anything but I can feel it sometimes when I urinate. I do a lot of sweating in the private area and I'm concern as to how to keep that area dry for it to heal. I'm 56 year old so I', post menopausal but I still sweat in that area a lot.