I have had a dime sized hard lump on the left  front part of my hair growth vaginal area. Its not on my lips or inside just right on the front. I am 24 and i have gotten this 2 or 3 times before, years apart, in the same exact spot. In the past, i have waited it out but im getting worried. Its tender to the touch, even from my jeans. I have gotten ingrown hairs and/zits before so know its not that, this is different, doesnt ever come to a head, just gets smaller over time and eventually goes away...What is this and why does it keep appearing in the same spot?

Help...