What to do if i was circumcised at 8 days old due to religious purposes but are there ever cases when they do it and a mistake occurs?

Yes mistakes occur: There have been mistakes where too much skin has been removed & others where part of the glans has been amputated whether performed by physician or as ritual by a Mohel. I have taken care of a number of these over the years. Fortunately "mistakes" are few & far between & Most circumcisions are fine. Hope you weren't recipient of one of these "mistakes".