Cause for red swollen penis. In some cases, untreated phimosis requires surgery. Not a valid value. If you are looking for health or medical advice we recommend that you: Infection — the doctor may prescribe antifungal or anti-inflammatory creams, oral antibiotics and pain-killing drugs. What is a penis cyst? Long periods of balanitis may be a cause for concern. Balanitis is swelling of the foreskin, or head of the penis. Penile Yeast Infection: Bellevue Everett Federal Way Seattle.