Suggest Medication For Bump On Left Labia Majora And Irritation Between Thighs

im 16 and im a virgin. im had irritation between my thighs a few days ago, this happens when i walk alot so my thighs rub together at the top this time it was itchy too. i always treat it with vasaline to soothe the burning, i just found a bump on my left labia majora its hard, painless and very very slightly red. im very worried. can i please have an idea of what tis is and how can it be treated? thank you.