Promise of paying money on simple paper

While in i college i played betting. I was under some debt and was mentally frustrated. I didnt had the money. I was being mentally harassed by the person whom I had to give money. So I wrote on blank paper that I have to give you money and I will pay the interest, So thay he trusts that i will return the money. Next day I gave it to him. Afterwards he said he had thrown the paper as he trusted me. After college I payed the debt in installments. Sometimes, I now worry whether he can use that paper against me in future as we are not in good terms in our personal relationship. I wrote a confession that I had to give you so and so amount and would pay so and so interest. The interest was also unrealistic. There were no witnesses neither he signed it himself. It's been six years now. Please advice. Shall I take some action in this regard. Also can he use that paper in court against me.