I am confused about something. In the New Testament, where Paul talks about if you are circumcised let you remain that way or if you are uncircumcised remain that way, does that mean that it would be wrong for a man who is circumcised to regrow his foreskin? I'm sorry I was just confused by that and have heard a few different opinions.
"Was any man called when he was already circumcised? He is not to become uncircumcised. Has anyone been called in uncircumcision? He is not to be circumcised. Circumcision is nothing, and uncircumcision is nothing, but what matters is the keeping of the commandments of God. Each man must remain in that condition in which he was called" (I Corinthians 7:18-20).
Far too many people think that they will be happy if something changes in their circumstance. A Jew, who was circumcised when he was eight days old, learning that circumcision is no longer necessary, may think he needs to become uncircumcised (if it were possible) to be pleasing to God. A Gentile, who was never circumcised, was told by false teachers trying to bind the Old Law on people that he needs to be circumcised before he can be a "true" Christian. Paul is saying it does not matter. Whether you are circumcised or not makes no difference in a person's life, so don't chase after these sorts of things. Be happy with who you are.
As of this time, I have not found any studies of non-surgical methods of restoring the foreskin. The evidence is just people making claims without verification. The non-surgical methods basically involve stretching the skin of the penis so that it covers the glans again; at least, in part. While the stretch skin covers, the question is: Does it remain stretched and for how long? The stretched skin cannot restore the inner foreskin with its specialized nerve endings. Even surgical restoration has not been studied with enough detail to know what the success rate might be.
It remains that it is not worth the effort to change. Be happy with who you are.