In january 2021 i got anal fissure and after suffering on/off for 6 months, finally my fissure healed completely. now sometimes i doubt and check the fissure again and again by putting lubricated finger in anus. can this cause fissure again?

An anal fissure is a tear, and I’m sure from your previous experience you know that it is a very painful condition especially with passing the bowel movement which causes stretching of the sphincter. Blind finger insertion can exacerbate it and so could even a single episode of hard stools. So important to stay regular. I would discourage examination just to check.

Probably can’t hurt but is not necessary and could create other problems. You know the symptoms of a fissure from your prior experience so if no symptoms, don’t think your self exam is going to be of any benefit and could be harmful. If in doubt, see a colorectal surgeon for a simple office exam that is more reliable and safer.