Sacred Haven of Debauchery

Hello everyone! A very big trouble has befallen my family; I suspect that my son is masturbating. I am a very devout woman, my husband is not around, and I am raising my child alone, instilling a love for our Lord Jesus from early childhood. My son is 14 years old. I was changing the bed and found semen stains on the sheet. I beat him severely with a belt until he had bruises and made him pray three times. I found ways to combat childhood masturbation on the internet. I tried to do everything as it said there (I took the door off its hinges, threw away all his magazines, threw away all his CDs (he also really liked rock music, but that's devilish music!), and I don't allow him to spend more than 10 minutes in the bathroom or toilet). After reading the article, I became even more scared! Now I'm afraid that my child will fall into the hands of pedophiles. He is also withdrawn and listens to rock (he is constantly on the computer, saying that he is learning to program, but I don't believe him; I think he is watching pornography on the computer, but I don't know how to check!). He is definitely masturbating! Now I beat him and punish him all the time (but he still denies that he is masturbating), and we pray together every day at least twice. I don't know what to do; please help me! May the Lord have mercy on our sinful souls!