Finasteride is not known to alter sensation over the penis. It is either due to some other problem or because you have read something about finasteride that is psychologically affecting you. Don't worry about it. If the tingling or pain is still present after a week of taking it please visit your dermatologist and tell him you are not comfortable taking finasteride tablets. Most of the problems caused by finasteride are psychological because there is so much negative publicity on blogs about it. If your desire to have sex (called as libido) reduces, that is probably because of finasteride and you should stop taking it. Your hair growth will not be as good without finasteride. Warm regards. Dr. Rajdeep Mysore. Chirag Hospital Bangalore