I left old makeup on for a whole day and after i took it off my left eye hurts when i close it and both eyes are discharging a lot. what do i do?

If it is a clear: "discharge" like tears and the eyes are itchy and the whites slightly reddened it is likely a viral conjunctivitis and not to worry. Use cold compresses, OTC artificial tears to flush for comfort antihistamines if they are helpful and wait 3-4 days. You should be improved. If anything other meaning thick continuous, opaque discharge or pain then see your doctor.