A red spot in the eye is most commonly due to a small broken blood vessel called a subconjunctival haemorrhage, which is usually harmless and clears on its own within 1-2 weeks, but since yours has lasted for 4 months, it needs proper evaluation. Possible causes include repeated minor trauma (like rubbing the eye), uncontrolled blood pressure, diabetes, or use of blood-thinning medicines. There is usually no specific treatment, but using lubricating eye drops can give comfort; the main step is to identify and treat the underlying cause. It is important to consult an eye specialist to check your eyes and also monitor your blood pressure and blood sugar, especially if you have related conditions. Seek urgent care if you notice pain, vision changes, or increasing redness.