Thanks for your question on Healthcare Magic. 
I can understand your concern. 
Painful lump in vagina or labia is mostly due to 
abscess or 
infected cyst. 
Most common cause for this is infection through sexual intercourse. 
So if you are sexually active, avoid 
unprotected intercourse. 
Other causes are poor genital hygiene, 
diabetes, poor immunity etc. 
So drink plenty of fluids orally. Avoid moisture and perspiration in private parts. Keep proper hygiene of private part. 
Get done sugar levels to rule out diabetes. 
Start 
multivitamin tablets. 
At present, you will need antibiotic cream for local application and oral tablets of painkiller and anti inflammatory drugs. 
Don't worry, you will be alright with all these. 
Hope I have solved your query. I will be happy to help you further. Wish you good health. Thanks.