I am 20 years old and I have a 2 year old pimple on vagina lip.. I too have oily skin.. I use hair removing cream there n sometimes do waxing too,

Totally normal. Though painful, and often turns into boils for me lol.
What works best is something I learned from other members on this site. A warm (almost hot) compress cloth, or soak in a bath tub for a while. And keep the area clean. It will go away on its own. Its just a pain in the patooey (pun intended!)