consult a experienced and good sexologist

some men who are preoccupied and severely distressed with the size of their penis may be diagnosed with body dysmorphic disorder...Penile shortening is a phenomenon that is associated with certain medical and surgical conditions. These conditions include prostate cancer patients treated with radical prostatectomy, Peyronie's disease and congenital anomalies. There is also some evidence that erectile dysfunction may be an independent risk factor for shortening... Standard measuringtechniques are necessary to diagnose the problem...Consult nearest urologist they will do the needful.

for masterbation: You must understand that excess of everything is bad. Same is true with masturbation. Control masturbition. Dont do more than a once in a week otherwise it may cause some weakness. You may take cap. Shilajit & tab. Chandraprabha bhati. One tab. Each morning & evening & also take dhatu paushtik churan one spoon morning & evening. All 3 with hot milk for 3-4 months.