Is there a disorder or syndrome for a person who have a habit of sucking there own tongue? why does this happen and the damage that it can cause?

No: Many people unconsciously put their tongue between their teeth because closing all the way on their back teeth puts a strain on muscles and thus joints.

No disorder : There isn't a syndrome or disorder for this. Most likely it's a habit. It most likely would cause an open bite. This is where you front teeth are not making contact with opposing teeth. It can also cause other malocclusion issues.