I have a large rough lump on the outside of my vagina on the left side and i dont know what to do?

Need examination: This is one of those questions that requires an examination by a doctor. There are so many possibilities. Without an examination it's hard to say what it is. A small cyst or folliculitis is what it sounds like but an Obgyn will need to see it to determine the next steps. If comfortable consider a virtual visit with a doctor in your state so an image of the area can be reviewed for better guidance