Um help? Unusual things on my parts!

Kayle
I have a mystery lump on my bikini line (inner thigh area) and it is pretty large. About as wide as my finger. Almost a cm tall, and about an inch long. Tender and has a blister looking area on it. Anybody know what this is or how to treat it? Not the first time I've gotten but usually goes away with in a day and never gets this big. I circled it a few mins ago to see is it progresses.