The lump having a sticky,brownish discharge seems to be a cyst
Please don't rub or squeeze it. Visit a surgeon. Usually such cysts are aspirated with a sterile needle & the aspirate is examined to locate the cause.
This is followed by a course of medicines depending on the characters of the aspirate. Many a times it subsides . If it refills, it needs a surgical removal.
Please get it properly evaluated & treated by a surgeon.