My penis swells and some foul yellowish discharge comes from the foreskin and it has been persistent because i treat and it comes again its been three times already for the past 9 years.how can i stop this ??

I assume you were not circumcised and have experienced recurrent balanopostitis. Circumcision is often advised to prevent recurrence. Consult a urologist.

If you are uncirc. then it could be a recurrent infection or irritation from accumulated smegma ( a secretions from the glands near there). You need to be examined Best is to see a Urologist for proper diagnosis and treatment. In the meantime keep area claen with daily soap and water wash. good luck