tmi...help

ive had a small bump on the outside of my vag for awhile now, like between my labia and leg,, lower though, the other day i noticed it had gotten bigger,,, theirs only one bump and its kind of red, before it wasnt red at all... i dont know what this is or why i have it...it didnt itch before but now it itches, --- tmi --- i tried to pop it but just some blood came out. anyone know what this could be?? help! please