A big bump in the upper inner part of my lips its really painfull when I close, my legs dats how I notice it I touch it and it burst yellow thick pus?

A Bartholin's Cyst. It is very ikely that you have a barthoin's cyst--it is typically not an infection but can be caused by infection which blocks the gland/duct, thus collection of fluid (swelling) to cause the "bump." this can be size of a pea up size of an egg. If not bothersome, no treatment needed. Yours is likely infected, antibiotic maybe needed and cyst may need to be excised. Consult your doc. Good luck.