Hello Dear. I feel you have balanitis or inflammation of the foreskin which causes penis to swell. Nacro tablet has got nothing to do with the swelling. Also kidney or prostate inflammation will not cause swelling of the shaft of penis. Balanitis is inflammation typically caused by infections or chronic skin conditions. Improper hygiene can contribute to skin irritation. Both inadequate cleansing and too much cleansing can add to this problem. The condition is often caused by an overgrowth of either bacteria or yeast. The foreskin of the penis is an ideal place for these organisms to grow because it can trap moisture around the penis head Injuries on the tip of the penis or foreskin can cause swelling and discomfort. Irritation in the area can also cause balanitis. Irritation can be caused by: not rinsing soap completely off of your penis after showering using scented soaps to clean your penis using bar soap that dries out the skin using scented lotions or sprays on your penis Discontinue the use of all perfumed soaps, lotions, or powders, as they are often are a cause of foreskin irritation. Use only warm water for cleansing Kindly consult a physician. After a diagnosis, your doctor will likely prescribe a medicated anti-itch cream. This cream helps stop itching and inflammation Hope i have answered your question. Feel free to contact me if you have any more questions. I ll be glad to help you. All the best With warm regards Dr Sanjay Kini