Quiet Bothered

I was really bothered a while ago at work. My Boss me handled me a money to pay for the engineer who signed the building permit. That engineer is also my Boss close friend, that was we know in the office. So when that Engineer came. I talk to him for a while and handled him some plan that  was miss out to sign and i handed him the pay. Then when he went  out of  office, I realized that I should have let him sign so that I have evidence that he really receive the money as his pay.  I was really bothered and I keep on thinking. I know his been signing building permit for my boss project ever since. I don't know what was their payment like before. Since I was really bothered because I think that I miss out something, I told my office mates about that and she advice me that I will just tell my boss about it. That I already gave the payment to that person and I was not able to let him receive. But still I think that was lack at my side. I just hope that everything will be okay. And I really learned a lesson from that situation. Next time.. I would really think fast and be wise.