lump on my lady parts.

tmi warning but i need help. yesterday I found a small hard lump under the skin of my labia minora, sitting more to the top just under the clit. a bit bigger than a grain of rice but smaller than a pea. it hurts when I touch it and today my pants and underwear are causing me discomfort and pain. I need this sorted ASAP as my job is a horse rider. it's my job it's affecting. I want to see a gynecologist but I can only an appointment 11th of January. I don't want to wait incase it gets worse. and idea what it could be and if it would be worth me seeing my general practitioner doctor about it? I'm sure it's not a STI as iv of only had 1 partner and he's clean.