You have not provided details, like, redness, itching, discharge, visual status. If only watering is there, that too for 15 days only, it can be due to foreign body, dryness, lacrimal duct blockage, or refractive error, etc. If other above mentioned symptoms are there then there can be allergy or infection.
Next Steps
Better to consult an eye doctor for foreign body removal, if any, glasses prescription, if needed, or management of duct blockage or allergy/infection.
Health Tips
Never use OTC medicines or eye drops on your own.