Hi Sivam, Welcome to HealthcareMagic Forum.
Your history suggests you have a Fungal Infection
, since you have Itching. You should be getting yourself examined by a Urologist
so that he can examine you and confirm it. You will require topical anti fungal medicines.
The normal Penis size, is between 8.5 to 10.5 cms when non erect, you don't require any treatment for this. Just eat healthy nutritious balanced diet which should include fresh fruits and Green leafy vegetables. Exercise regularly and maintain a Healthy weight.
is absolutely harmless and it wont cause any weakness or affect your future sexual life. Do it only when you are sexually aroused may be twice or thrice a week.
Wish you Good Health.
All the Best.