Here is a YouTube video that explains how sutures affect a wound in general (not circumcision specific):

What Happens If You Leave Stitches in for Too Long?

There seems to be some confusion about what to do with stitches. Some of us keep telling people that they need to come out around day 10 otherwise they WILL leave some permanent scarring. Doctors seem to have an attitude that they fall out when they fall out and don't necessarily want to deal with removing them. It is hard to give proper advice on the subject, after all they should be removed by a health care professional.

The problem is that afterwards people post pictures a few months post op sometimes with desperate pleas what to do to make stitch marks disappear. While there are ways to make them fade to some degree, really the best option is to prevent them from appearing in the first place by removing stitches as soon as they are not needed.

Circumcision wounds typically heal well enough in a week of so that stitches can be safely removed, so getting them out after 8-10 days should be fine. That is really the best thing you can do if you want to avoid railroad tracks. While they are not the end of the world and they do fade somewhat over time, if you are very self conscious about how your scar looks, you need to be proactive. Trying to fix it after you have mature suture marks is really only possible if you have a revision and then you have make sure that it heals properly (otherwise everything just starts over).

Original source