3-4 years back I did a library internship, that required us to enter the time when we arrived and left. The recorded time was totalled and written on the certificate. Sometimes I didn’t enter the right time! Probably 3-7 mins (more or less) earlier. The issue I realise now is that I wasn’t really honest in filling the time, so the time on certificate is not exactly in which I worked in. What should I do now, to compensate for my dishonesty?
(Just to inform I haven’t used the certificate elsewhere to show it as an achievement.)

If you can talk with your library in charge or coordinator and explain him I’m sure he will be happy to listen and In’Sha’Allah you will feel peace.