Welcome to HCM This is Dr Amit. Let me help you in this case Normally it is superficial dorsal vein of the penis which drains the prepuce and skin of the penis and running backward inclines to the right or left and opens into the corresponding superficial vein. Veins in your penis will usually have a blue color but sometimes you may have what looks like a vein appear that wasn t there before. It may be accompanied by some swelling particularly around the corona (head) of your penis and often it appears after some vigorous sexual activity. This is often a lymph channel inflammation. Lymph channels usually follow near blood vessels, but the lymph system has no pump to move the fluid. It is usually accompanied by some discomfort,swelling and soreness. Treatment REQUIRES leaving the area alone. That means no sex or masturbation until at least a week after it appears to be completely healed Hope i have given satisfactory answer to your query Regards