Hello, Swelling on penis after having sex or masturbation can occur due to mechanical trauma to the penile skin or friction which can also cause pain and redness or itching. This could be due to vigorous sexual intercourse which tend to injure the smaller tissues like glans, frenulum and foreskin of penis. You can take short course oral anti-inflammatory medication with anti-allergic drugs available over the counter and apply antiseptic cream with mild steroids (Betnovate-N) which will reduce swelling,redness and inflammation. You have taken Tab. Doxy and Nuforce which are anti-bacterial and anti-fungal drugs which would be effective if there will be respective infections. Avoid sexual activity for 1-2 days and then observe for disappearance of swelling and pain. You will start improving within 2 to 3 days of this oral and topical drugs. To avoid future recurrence, use lubricants like KY Gelly or Vaseline during sexual activity. If the swelling and pain do not subside or there is appearance of discharge or any other similar symptom, you need to consult your GP (if surgeon or dermatologist appointment is not feasible) for proper clinical assessment and treatment. Hope I have answered your query. Let me know if I can assist you further. Wishing you all the best. Regards, Dr. Iven Romic Rommstein, General Surgeon